I am happy to be here at the Lindau meeting for the first time for me, and I'm pleased

to be able to speak about molecular structure in relation to medicine. This is a small part of a great subject, chemistry, in relation to medicine, a subject

that I shall not attempt, of course, to cover as a whole. I shall talk about molecular diseases and a little bit about a new theory, rather new theory of general anesthesia.

Now, in a sense, of course, almost all diseases are molecular in that the human body is made up of molecules and the vectors of disease, viruses, rickettsia, bacteria, are made up of molecules, so there are some diseases I think that we could say clearly are not molecular

diseases. If, as a result of an accident, a man loses a large part of his brain tissue, he has mental disease, it is macroscopic in nature, the molecules that remain to him are no different from those that he had before.

Or even if his brain is injured by anoxia, so that damage is done, or some other organ is injured by anoxia, although we might say that the injury is chemical in nature, I would not say that the disease that results is a molecular disease.

Some years ago, nearly 20 years ago now, the idea that the disease could be a molecular disease occurred to me. I should say that today I am not going to try to cover the whole subject of molecular

structure in relation to disease, but just those aspects of this subject with which I have some special acquaintance or in which I have a special interest. Some nearly 20 years ago, when I was serving as a member of a medical research committee

investigating the support of medical research by the United States government, one of the members of the committee talked about the disease sickle cell anemia. This is a disease, a hereditary disease, in which the red cells in the blood are twisted

out of shape, and as a consequence of the deformation of the red cells in the blood, the patient has a serious anemia, his red cells are destroyed so rapidly by the spleen

that he is not able to manufacture new ones rapidly enough to keep him in good health. And also, these deformed red cells clog up the capillaries in crises of the disease so that the blood ceases to flow through some organ, and the organ is damaged by

anoxia. The statement that was made that was most interesting to me and that immediately brought a response from me, was that the red cells are twisted out of shape in the veins, in the venous circulation, but resume their normal form in the arterial circulation.

Now I have liked the hemoglobin molecule for a long time. In 1934, I began to work on the hemoglobin molecule, and it seemed clear to me that

there was a high probability that it was the hemoglobin molecule that was involved in this difference in behavior of the red cells of these patients, so far as of the red cells in the venous blood and in the arterial blood.

The hemoglobin molecule contains about 10,000 atoms. Four of them are iron atoms. In the lungs, an oxygen molecule can attach itself to each of the four iron atoms.

The blood charged with oxygen in this way circulates out to the tissues, and the oxygen molecules are given up. The difference between venous blood, the principal difference between venous blood and arterial blood is that venous blood contains molecules of hemoglobin without oxygen

attached to the iron, and arterial blood contains molecules of oxyhemoglobin. Well, the suggestion then that it is the hemoglobin that is involved brought a further idea that the patients with this disease manufacture an abnormal sort of hemoglobin

that is self-complementary so that the molecules clamp onto one another to form long rods which line up side by side as a crystal or perhaps tectoid liquid crystal of hemoglobin, which as it grows longer and longer twists the red cell out of shape

and leads to the manifestations of the disease. When the iron atoms are oxygenated, the self-complementariness may be destroyed in such a way that the crystals go back into solution and the cells resume their

normal shapes. When I returned home to Pasadena a few months later, a young man, Harvey Itano, who had received his MD degree came to work with me, and I asked him to examine the

hemoglobin of patients with this disease and to compare the hemoglobin of these patients with the hemoglobin of normal individuals. For three years, he made comparisons of hemoglobins from these two sources and always with the same result in every experiment that he carried out.

Well, with a substance so complicated that its molecules contain 10,000 atoms, the identity, apparent identity of certain properties is no assurance that the molecules are completely identical in structure.

Finally, he carried out one experiment. He and two other young men, Dr. Singer and Wells, then working with him, carried out one experiment, an electrophoresis experiment in which the two samples of hemoglobin behaved differently. That was enough to show that they are different, this one experiment with such a

complicated substance, any number of experiments in which they behaved the same would not be proof of identity. Many other abnormal human hemoglobins have been discovered since 1949, and

many abnormal or different hemoglobins manufactured by other animal species, several hemoglobins by the same species of animal under the control of the course of genes. I believe that I shall continue now with the slides.

Here we have, and perhaps it is, I can say as a tribute to Professor Mecke, as well as to my fellow Californians, both now dead professors,

they were young men then, Drs. Latimer and Rodebusch, who in 1920 discovered the hydrogen bond that I start out with a picture of a molecule containing hydrogen bonds, the dimer of acetic acid.

The hydrogen bond is of such great importance in the molecular structure of the human body that I have chosen to start with this representation. The two oxygen atoms bonded by a hydrogen atom are 2.79 angstrom apart,

and the two bonds together amount to about 14 kilocalories per mole. The next slide. This is an old drawing going back some 15 years indicating that in the polypeptide chains of proteins, stable structures will be those in which the

polypeptide chain is folded in such a way that hydrogen bonds are formed. At the time that this drawing was made, no configuration of polypeptide chains had yet been discovered. None of the configurations in which the polypeptide chains occur in nature.

The next slide. This shows the folding of a polypeptide chain into the alpha helix. The peptide groups are planar because of the partial double bond character of the carbon nitrogen bonds here, stealing double bond character from the

carbonyl group of the amide. There is a central freedom of rotation around the single bonds to the alpha carbon atoms. The folding is done in such a way that each hydrogen atom attached to nitrogen is able to form a hydrogen bond with the carbonyl oxygen in the

peptide group three removed from it along the chain. There are 3.6 amino acid residues per turn of the helix. The next slide please. The pitch, the distance along the helical axis per residue is 1.49 angstrom.

The dimensions of the alpha helix have been very well verified by experiment for the synthetic polypeptides with the alpha helix structure for alpha keratin, fibrous proteins, hair, horn, fingernail, porcupine, quill, and so on.

Also, through the work of Kendrew for the polypeptide chain of the globular protein myoglobin. That's next to Bill Pippin here.

Myoglobin and Professor Kendrew will, I hope, speak in detail about his great feat in making an essentially complete structure determination of the myoglobin molecule. Myoglobin contains eight alpha helix segments, one of which is shown here.

The iron atom is up in the upper right-hand corner surrounded by the atoms of the porphyrin group that constitute with the iron atom the heme group where the oxygen is attached. Now here we have a patient with the disease sickle cell anemia.

This disease seemed to be a disease of the red cell and it turned out to be a disease of the hemoglobin molecule. The next slide. In the oxygenated blood of these patients, the red cells have a normal

appearance when seen through the microscope. In the deoxygenated blood in the veins, they are sickled. The red cells are sickled. When this investigation was first carried out showing that the patients produce an abnormal hemoglobin, the parents of a patient were studied.

It was found that the father contained in his red cells a mixture. 50% of the hemoglobin was normal, 50% abnormal. Similarly for the mother. This next bill. Here we have a paper chromatographic study.

The diagram on the far right is the best. It corresponds to four hours of electrophoresis. At the bottom is a hemoglobin from a normal individual. It migrates rapidly. It has a large negative electric charge.

Directly above it is the hemoglobin from the father or mother of a sickle cell patient. Here there are two hemoglobins, normal hemoglobin and sickle cell hemoglobin. The sickle cell hemoglobin migrates at a rate showing that it differs in its electric

charge by two electronic units. It has two fewer negative electric charges than the normal hemoglobin has. Dr. Itano brought into the laboratory a sample of blood from another person.

When he investigated it, it was found that this person had sickle cell hemoglobin in his red cells and another hemoglobin still more abnormal than the sickle cell hemoglobin. With four units of charge difference from normal hemoglobin.

One parent of this interesting individual was a sickle cell heterozygote. The other was a heterozygote in this new abnormal hemoglobin, manufacturing both normal hemoglobin and this new abnormal hemoglobin. In the theory of heredity, Mendelian heredity, one would expect that parents of this nature,

two heterozygotes, would have children of several different kinds. One quarter of the children would inherit the abnormal gene of the father and also

the abnormal gene of the mother and would then have a double abnormality, each present in single dose. This person had the disease of a new kind, a disease involving the inheritance of two different abnormal genes which separately do not produce any serious disease.

But they cooperate with one another to produce a new type of anemia. The disease is called sickle cell hemoglobin C disease. This hemoglobin was named hemoglobin C. Many other hemoglobins have since been discovered, hemoglobin D, E, G, H, and so on.

Scores of human abnormal hemoglobins are now known, so many that I can't keep up. Next slide, please. A few of them are indicated here. Along the diagonal of this matrix, we have some of the homozygotes.

The sickle cell patients with two sickle cell genes, hemoglobin C patients with two sick hemoglobin C genes, and so on. At the top are the carriers of the genes in single dose. They in general do not have serious diseases.

Then we have on the diagonal some of the complex diseases involving the inheritance of two different abnormal genes in the manufacture of two abnormal hemoglobins. The next slide. Dr. Schroeder and our laboratories and his collaborators using the method of Sanger

were able to show that there are two kinds of polypeptide chains in the normal hemoglobin molecule. One chain contains 141 amino acid residues.

It is called the alpha chain. It begins with a residue of valine and continues leucine, serine, proline, alanine, asparagine, and so on. The beta chain, the other chain, begins valine, histidine, leucine, threonine, proline, glutamic acid, and continues on.

The English investigator, I'll think of his name in a moment, what's that? Ingram. Vernon Ingram developed a technique of two dimensional paper electrophoresis chromatography and the splitting of hemoglobin into several simple peptides.

He was able to show that the abnormality in sickle cell hemoglobin is in the beta chain. He and Dr. Schroeder tied it down to the sixth position in the beta chain where valine replaces glutamate.

The glutamate residue carries a negative electric charge. The carboxylate group is ionized and the valine has a negative electric charge. The hydrocarbon side chain with no electric charge. Consequently, one negative electric charge is lost from this substitution.

The next slide, please. There are two beta chains in the sickle cell hemoglobin, two alpha chains and two beta chains, just as in normal hemoglobin. But the beta chains are changed by the substitution in the sixth position in the

beta chain, giving them a difference in electric charge of two units and a difference in molecular structure such as to produce the complementariness and insolubility characteristic of sickle cell hemoglobin. We do not yet, despite the work of Perutz in Cambridge, we do not yet know the

structure of the hemoglobin molecule well enough to be able to explain in terms of structure the formation of the tectoids by deoxygenated hemoglobin S.

But we can expect that this will occur soon. Here there is a symbol given for hemoglobin F. The letter F stands for fetal. Hemoglobin F is the hemoglobin that is manufactured by the fetus. It contains two normal alpha chains resembling the adult and two gamma chains,

which are rather different from the beta chains. At about the time of birth of an infant, the infant begins to manufacture beta chains, whereas earlier in life, in prenatal life, he was manufacturing gamma

chains. Next slide, please. This is the technique that Ingram used of hydrolyzing a protean with trypsin, the hemoglobin, to produce about 26 peptides, each with 10, 12, 14 amino acid residues in it, separating on the paper by electrophoresis in this

direction and by chromatography vertically. Only one of the 26 peptides is different in sickle cell hemoglobin from normal hemoglobin. It is represented by this spot, which is moved to this position. When this peptide was investigated, it was found to be the first peptide in

the beta chain and to have glutamate replaced by valine. The next slide. Here we have results indicated for some other abnormalities of human hemoglobin

molecules involving the beta chain. Many abnormal hemoglobin, human hemoglobins are known in which the alpha chain is abnormal. They are not shown here. There are 146 amino acid residues in the human hemoglobin beta chain.

They are all known. Only 31 are indicated here in the first line across here. In the case of hemoglobin S, sickle cell hemoglobin, as I have mentioned, in the sixth position, glutamate is replaced by valine. With hemoglobin C, glutamate is replaced by lysine.

Now lysine has an amino group attached to the delta carbon atom of the side chain, and it becomes an ammonium ion group at physiological pH so that the lysine side chain carries a positive electric charge.

The glutamate, a negative electric charge with two beta chains in the molecule, this means a difference of four units of electric charge between hemoglobin C and normal hemoglobin. Hemoglobin G has a substitution in the seventh position.

Hemoglobin E, a substitution in the 26th position. Hemoglobin A2, a substitution in the 22nd. It is accident that all of the substitutions that are indicated here involve replacing a glutamic acid residue by some other residue, other

kinds of substitutions are known. In each case, as for example hemoglobin S, sickle cell hemoglobin, there is only one amino acid residue changed. All of the other 140 are exactly the same as in the normal adult human hemoglobin.

No variant of human hemoglobin has been discovered in which either the alpha chain or the beta chain differs from normal by more than one amino acid residue.

The next slide shows the geographical distribution of the gene for sickling. Central Africa, Madagascar, and then this is Atlantis I think down here. Then various isolated occurrences reported, and of course in the United States,

in Sicily, southern Italy, Greece, these regions. Over in Portugal, there are numbers of people who carry the sickle cell gene. One can ask why this gene has spread so widely among the human population.

There must be some advantage to carrying the gene in order for a mutation to begin to spread. The answer was suggested by a British physician, Dr. Brain, who noticed that there were more sicklers, people whose red cell sickled,

in malarial regions in Africa than in nonmalarial regions. Then a young physician, Dr. Anthony Allison, carried out a crucial experiment in Kenya. He got 30 healthy adult Africans, male, who were shown by skin tests

not to have developed any immunity to malaria. When they were inoculated with malignant sub-tertian malaria, 15 of these who were normal people, so far as their hemoglobin goes, became ill.

14 of the 15 became ill with malaria. Of those who had one sickle cell gene, the heterozygotes in the sickle cell gene, only two came down with malaria. There was a great degree of protection against malaria by a single gene.

Their red cells contain a 50-50 mixture of normal hemoglobin and sickle cell hemoglobin. This provides them with protection against malaria. There is a molecular mechanism, of course.

Ordinarily, the red cells of these individuals, the heterozygotes, do not sickle in the venous circulation. But if the blood is completely deoxygenated, then the red cells are twisted out of shape. The crystal forms, even though the hemoglobin is diluted with an equal amount of normal hemoglobin.

The malarial parasite lives inside the red cell. The parasite has a high metabolic rate. He uses up the oxygen inside the red cell so that the partial pressure of oxygen becomes so low

that the hemoglobin crystallizes, twists the red cell out of shape, and squashes the parasite to death. We have a molecular explanation, not only of the lethal manifestations of the abnormal hemoglobin in the homozygotes,

but also of the protection against malaria that is provided to the heterozygotes. This shows the incidence of hemoglobin C. High incidence in northern Ghana, low in southern Ghana, and then still smaller along the coast here.

It seems likely that the hemoglobin C mutation occurred only a short time ago, perhaps a thousand years ago, whereas the mutation producing the sickle cell hemoglobin may have occurred 5,000 or 10,000 years ago and then have spread over Africa.

The next slide. Now I want to discuss another type of disease also related to hemoglobin and I begin by showing again the structure of myoglobin.

I point out to the iron atom and a group here that is rather close by the iron atom. This group is a histidine residue. It is in the 58th position of the beta chain or the 63rd position of the alpha chain.

58th of the alpha chain, 63rd of the beta chain. This group is, I believe, responsible for the retaining of the iron atom in the ferrous state.

Hemoglobin can also be called ferrohemoglobin. The iron is bipositive, bivalent. Sometimes hemoglobin is oxidized to the tri-positive state. The iron becomes ferric rather than ferrous. This ferrihemoglobin, also called methemoglobin,

does not have the power of combining reversibly with oxygen so that the power of transferring oxygen from the lungs to the tissues is lost. Now, ordinarily, ferrous compounds are easily oxidized to the ferric state.

This residue of histidine has an imidazolium ring in its side chain. The imidazolium ring at physiological pH adds a proton and assumes a positive charge. I believe that this positive charge in the neighborhood of the iron atom

stabilizes the ferrous state by repelling the additional positive charge that would be added to the iron atom to convert it from iron plus two to iron plus three. There is good evidence for this now through the investigation of the hemoglobins

of certain people who have a disease in which half of the iron atoms, two of the iron atoms in their hemoglobin molecules are easily converted and naturally converted

to the tri-positive state, to ferric iron. Dr. Gerald has been responsible for much of the investigation of the hemoglobins of these patients with the disease methemoglobinemia or ferrihemoglobinemia.

The next slide. Here we have the group of some 60 atoms that is called the heme group with the iron atom at its center bonded to four nitrogen atoms of four pyrrole rings and so on in the way that Professor Fisher, Hans Fisher, showed 60 years ago.

Next slide. Without having knowledge of the dimensions, of course, that we have now. Here we have the heme group with the side chain of histidine, the inadazolium cation, carrying a positive charge

that stabilizes the ferrous state of the iron. This you find in normal persons. Next slide. Now here is a type of variant hemoglobin, hemoglobin seric, in which in the beta chain, 60 second position,

in place of histidine there is a residue of tyrosine. Tyrosine with the para-hydroxybenzene ring does not pick up a proton. It does not carry a positive charge. The iron atom easily oxidizes to the ferric state

and the patient has the disease ferrihemoglobinemia. The next slide shows another abnormal hemoglobin in which the same histidine residue is replaced by arginine. Now arginine has a guanidine group in its side chain

that picks up a proton to produce the guanidine cation. The positive charge stabilizes the iron atom. It does not oxidize to the tri-positive state and these people, even though they carry an abnormal hemoglobin with the abnormality in this critical position,

do not have the disease ferrihemoglobinemia. The next slide. Here we have a few of the abnormal hemoglobins related to this state. Here is a beta in which, well let us go to this one. Boston has tyrosine in the 58th position

of the alpha chain. Emory has tyrosine in the 62nd position of the beta chain. They both lead to ferrihemoglobinemia. Zurich has arginine in this position, 62nd in the beta chain,

but without producing ferrihemoglobinemia. An interesting abnormal hemoglobin is Milwaukee, which has glutamic acid in a position four removed from histidine. The alpha helix has nearly four residues per turn of the helix.

This residue of glutamate is near the iron atom too. Normally there is valine in this position which does not carry a charge. The negative charge of glutamate apparently attracts an extra positive charge to the iron atom, which becomes the ferric iron atom and produces ferrihemoglobinemia.

Here we have a disease then for which there is a simple detailed chemical explanation of the manifestations of the disease. It will be hard to go beyond this, deeper than we have gone now

with this group of diseases in understanding disease on a molecular basis. The next slide, please. I should like to mention some evolutionary considerations. These involve studies carried out in our laboratories mainly by Dr. Amy Zuckerkandel from France

with the Centre Nationale de l'Arche Sarcéntif. We have here the peptide patterns using the method of Ingram for human hemoglobin, fish hemoglobin, shark down here,

hogfish, echiorid, worm. It is clear that there are great differences in the hemoglobins. In fact the differences look to be greater than they actually are because there are great similarities too even between human and fish hemoglobins. The next slide. We see now a comparison

of human, cow, and pig. It is evident that the patterns are somewhat similar. The hemoglobin structures are rather similar. The next slide shows human, chimpanzee, gorilla, orangutan, rhesus monkey.

If we compare human and gorilla or human and chimpanzee, it is nearly impossible to find the difference. A more detailed investigation shows that the alpha chain

of the gorilla differs from the alpha chain of the human by two amino acid residues out of 141. The other 139 are the same and in the same positions. The beta chain of human and gorilla, the beta chains differ by one amino acid residue

only. In the case of chimpanzee, the beta chain of chimpanzee differs from that of human by one amino acid residue. It is identical with a type of human beta chain, human hemoglobin called Norfolk hemoglobin.

Probably an independent mutation however in the case of the beta chain of the people in Norfolk who have this similarity identity with the chimpanzee beta chain. With rhesus monkey, instead of one or two differences, there are six or eight differences.

With horse, there are 18 differences, 18 amino acid residues out of 141 or 146 that are different. The next slide. Dr. Zuckerberg and I thought that we would try to make some statements about the process of evolution. We took

horse and human hemoglobins and assumed that the line leading to humans and horses, these lines separated 130 million years ago. That's why the brackets are here. This is the starting point. Then we assumed that there is a constant rate

of mutation, evolutionarily effective mutations. With this assumption, the gorilla alpha chain corresponds to 14 million years ago. The beta chain to seven, the average is about 11 million years ago. I don't have a comparison of human and rhesus monkey

down, but it would come out about 40 million years ago. This at once answers a question that the students of evolution have asked, at what stage did the monkeys of different kinds and the anthropoid apes and man, at what stage did these lines separate

from one another? The monkeys separated off from the common ancestor of gorillas and human beings about 40 million years ago. The humans and gorillas and human beings separated roughly 10 million years ago. Like this, 260 million years ago

is when human fetus separated from a human adult. Of course, there weren't humans then. It was when fetuses separated from the adults. A human fetus is more like a horse fetus in its hemoglobin, the beta chain or gamma chain of its hemoglobin, than like an adult

human being. In a sense, so far as the gamma chains, beta chains go, the fetuses of mammals are more closely related to one another than they are to their corresponding adults. The alpha chain and the beta chain have about 78 differences

and some 60 identities, corresponding to about 600 million years ago. The identities are so numerous that we can be sure that they originally represented a single gene, a single chain. Next slide, please.

We have attempted to determine the nature of the single polypeptide chain of the hemoglobin manufactured by the ancestor of all vertebrates some 600 million years ago. Here we have just four different chains indicated.

As we move along, we see that in this position, all four have lysine. In this position, three of them have leucine and the fourth has phenylalanine. It looks as though the fetal gene has undergone a late mutation.

After the separation of the genes for beta and gamma, gene duplication followed by independent mutation, the mutation occurred in the gamma gene. The next slide shows our present knowledge about the amino acid sequence in the polypeptide chain for hemoglobin manufactured

by the common ancestor of all vertebrates some 600 million years ago. There are some uncertainties, great uncertainties, about half the positions are not filled. Here there's one position not filled, another one with no knowledge, another one in a few years more, I'm sure

that all of these positions will be filled. It might then be possible to synthesize the polypeptide chain, add the heme to it, determine the oxygen-combining power of this primeval form of hemoglobin, and in that way make a decision,

reach a conclusion about the partial pressure of oxygen in the atmosphere on Earth 600 million years ago. The next slide, now I shall talk briefly about another application of molecular structure to a

problem that we can call a medical problem, the problem of the nature of general anesthesia. There has not been any satisfactory theory, perhaps there still is no really satisfactory theory, but there has hardly been a theory of general anesthesia until the theory that I shall

describe was developed about four years ago. I published this in June of 1961, and a few months later a young chemist, Dr. Stanley Miller, Professor Stanley Miller in the University of California in San Diego, published essentially the same theory,

quite different words and different calculations, but I think it is the same theory. I have here a drawing of the structure of ordinary ice. Each water molecule forms four hydrogen bonds with its four neighbors. It looks as though there are holes in this crystal, but

these holes are really not very large. No molecules except helium and hydrogen I think could fit into these holes up here. Now the next slide shows another view of ordinary ice looking down the hexagonal axis. The atoms are really much larger

so that the holes are small. Next slide. Here we have an aggregate of 20 water molecules forming 30 hydrogen bonds with one another. The bond angles within the pentagonal dodecahedron are 108 degrees so that no bond angle strain

from the tetrahedral angle 109 degrees and a half is involved. Investigation of hydrate crystals showed that these pentagonal dodecahedron of 20 water molecules occur in many of them. The next slide.

This is the structure, the basic structure of chlorine hydrate, methane hydrate, xenon hydrate. I was especially interested this structure was determined by Dr. Marsh in our laboratory 12 years ago. I was especially interested in xenon hydrate, the fact that xenon forms crystals

with this framework. Xenon atoms occupying positions at the centers of the polyhedra. There are six extra water molecules in addition to the forte of the two dodecahedra. The next slide shows that there are not only the dodecahedra but also

tetrachydecahedra in the centers of which somewhat larger molecules such as methyl chloride or cyclopropane or chlorine can fit. These crystals with a rather open framework, hydrogen bonded framework of water molecules are stabilized by the van der Waals interaction

of the xenon molecules or cyclopropane molecules or other molecules that occupy the cavities with the water molecules. The next slide. This is a larger cavity formed by 28 water molecules. It has four hexagonal faces

and 12 pentagonal faces. It is large enough to permit a molecule of chloroform, CHCl3, to fit inside it. In the chloroform hydrate crystal, CHCl3 17 H2O, there is one of these

polyhedra for every two dodecahedra. If xenon is present, the melting point, the decomposition point of the crystal is raised by 14 degrees centigrade, from 2 degrees to 16 degrees centigrade

because of the van der Waals interaction of the xenon molecules with the neighboring molecules. There's a cooperation then in this crystal to xenon CHCl3 17 H2O, a cooperative effect involving the xenon in stabilizing

the crystal. The next slide. This is a still larger opening in a hydrogen bonded framework in which there is a tetra-isoamyl- ammonium ion and a fluoride ion also present. I was reading a manuscript describing a crystal of this sort,

not yet published, paper sent to me by Professor Jeffrey back in 1959, April 1959, when I thought to myself, I understand the mechanism of anesthesia, general anesthesia. Here we have an ion,

something like the side chain of a lysine residue in a protean, perhaps in the brain. These electrically charged side chains and some ions interact with the water molecules to form small crystals of a hydrate. And in the presence of an

anesthetic agent, which can fill other cavities, xenon, for example, which serves as a good general anesthetic. It isn't used because it's so expensive. Xenon molecules, xenon atoms could occupy some of the smaller cavities and stabilize the crystal, which, however, would also

involve some ions from the solution and some of the side chain groups of proteins. This would trap the electrically charged side chains and ions, which normally oscillate back and forth, contributing to the electric oscillations in the brain that constitute consciousness and

ephemeral memory, and by decreasing the amplitude of the electrical oscillations would lead to unconsciousness. Then, as the anesthetic agent is allowed to leave the body through the lungs, the crystals would become unstable and would decompose again, and the

consciousness would be regained. If this theory were right, then it should be possible to anesthetize people by cold, just by cooling the brain. Of course, I discovered that it is possible to produce anesthesia just by cold. At 30 degrees

centigrade, mild anesthesia is produced at 26 degrees deep anesthesia. Next slide, please. Also, if this theory is right, there should be a close relation between the van der Waals forces, between the anesthetic molecules and other molecules, and

the anesthetic activity. Now here, I have plotted the logarithm of the equilibrium partial pressure of the hydrate crystals of various anesthetic agents against the molecular polarizability expressed here in cubic centimeters

per mole. The high pressure, nearly 100,000 millimeters of mercury is required to produce argon hydrate crystals, methane, krypton, and so on, xenon down here, methyl chloride, ethyl bromide, chloroform, carbon tetrachloride.

We have this curve. Over here is the curve similarly plotted against the molecular polarizability. The logarithm of the narcotizing or anesthetizing partial pressure for mice at 37 degrees centigrade. The curve has the same

smooth character. Next slide. Here, I have plotted the anesthetizing partial pressure logarithm of it against the logarithm of the equilibrium partial pressure of the hydrate crystals. There is a reasonably good linear relationship which goes over a great

range of pressures. Here, we have 10, 100, 1,000 some 3,000 fold range in anesthetizing partial pressures between chloroform and argon as shown on this curve. This is then some indication

that it is the molecular polarizability that is responsible for the anesthetic activity, not necessarily the formation of hydrate microcrystals. There might be some other way in which this molecular property could be acting, but I

think that the hydrate microcrystal idea is a good one. The next slide. Here are some experiments, not yet published, carried out with goldfish in which, here we have the temperature, the reciprocal temperature, temperatures above running from zero

degrees over here, 1.6 degrees to 35 degrees. For these several anesthetic agents, the temperature coefficient of the anesthetizing partial pressure, the logarithm is shown here plotted against the reciprocal of the temperature, corresponds

over a wide range to a nearly constant enthalpy of reaction with nearly the same value for the different anesthetic agents. Then there is a rapid drop. The goldfish are anesthetized at 1.6 degrees

centigrade, even in the absence of the anesthetic agent. This sort of catastrophe, of course, indicates a cooperative phenomenon, such as crystallization, a phenomenon in which a large number of molecules take part, a change in phase.

I think that this is a good indication that something that we might call microcrystal formation is taking place. The next slide, please. This is another representation of the crystal of xenon hydrate in which there's

the hydrogen bonded framework of water molecules with a xenon molecule, monatomic molecule, occupying each of the dodecahedral and tetrakaidecahedral cavities. I am pleased that a reasonable theory...

Lights, please. I am pleased that it is possible to propose an explanation of the extraordinary property of xenon, highly unreactive substance,

which surely does not enter into ordinary chemical reactions in the human body, of producing anesthesia when it is inhaled. I think that it is possible to understand the molecular structure

of the human body, to understand physiological phenomena, even psychic phenomena. I believe that it will be possible to get a penetrating and deep understanding of the nature of mental disease in the course of time, such as to permit great progress

to be made in the control and treatment of mental disease, which is one of the great scourges, of course, in the world today, and the cause of a tremendous amount of human suffering. We are just entering now on the period

of development of molecular biology and medicine. The ideas are necessarily rather crude ones that have been proposed so far, but I think that we can have great

hope for the future. Thank you.