nothing about anything else. There is a sense in which we know something about plowing, something about sowing, something about planting, and something about the action of medicine.

Dr. ODELL: The underlying idea that I had in the first place was that, whereas, we always sneer at the word empiricism, about all we know of medicine is empirical, and what we call science is simply the classification of empirical discoveries. It is the part of science to give a reason for what empiricism always discovers. I want to disclaim the idea of attempting to criticise the remarks of any one. I only wish to criticise the ideas which these remarks seem to contain, as coming from apparently such high authority. The way in which some of these actions go on we have learned to a certain point, and we have learned it because we first discovered that such was the action, and then we experimented and saw the same results follow the same causes, but when you come to try to define the effect that certain medicines have upon certain organs you are at fault; and yet more so, when you attempt to follow out the mode of action as upon masses, molecules, and atoms. In the oxygenation of the blood we think we understand the "how" by a mere transference of oxygen to a molecule which demands it, and which is ready to affiliate with it, but when you come to the action of any other known thing upon the tissues of the body, we can merely make a hypothetical statement as to what takes place. Beyond this we enter into the domain of the breaking down of molecules into atoms, and the recombination of those atoms, of which we as yet know very little. Dr. WATT: If we have a knowledge of the action of oxygen, we know how one medicine acts, and that carries the point.

Dr. ODELL: That is our type, and that is the reason for trying to find out more, but we have not got that far yet.

Dr. ATKINSON: We talk of tonics and we talk of stimulants. Let us see if we can make a statement that will define the action so as to be comprehensible. We have a functioning body made of molecules. There is no such thing as cell-action alone; it is molecular action in combination, that is, a host of molecules gather together and group in a small body that we call a granule, whereby we get that mass-action that we are able to perceive by the senses. But there is a finer mental sense of reasoning by which we must perceive the change that occurs between the pabulum and the needy body, so that it shall be fed. This impact of energy that operates upon a hungry molecule, that does not combine with it, but simply awakes local energy in it so as to perform the function belonging to

the part, is a stimulant. Any impact or substance that is taken into and combined with the molecule, therefore, becoming part and parcel of the molecule, is a tonic. Tonic then is a food in every instance. The stimulant is the action by presence, referred to by my friend who last occupied the floor. If we make a few of these simple corrections we will regard with less reverence the massive nonsense that has been presented to us as physiological and pathological activity. One word in relation to matter being dead: Every atom has a living and a dead side-that is, a dynamic and a static side, a side of energy and a side of statism or absolute massism. It is doubtful whether we can conceive that atoms ever originated, but when we trace them we find them endowed, as is said, with power, that is, in their normal condition; in their dead condition, when we examine them as atoms, they are in a sleeping state. What is it that sleeps? It is the dynamism, it is the power, it is the energy that resides in it that is omitted,-I do not want to say cause, but I have to say it, -that is motion,-for we really know nothing of causes, we simply know their incidents and consequences. If you have the point, it is this, that we must be more careful in discriminating about these things, whether they be foods, whether medicines, or whether they be poisons. Anything that can act upon a molecule can be denominated either food, poison, or medicine.

Professor MAYR: Dr. Watt said that arsenic killed certain lower organisms, and that they were eliminated. This is what I plainly and squarely deny. As example I give the fact, that in my laboratory there were two bottles in which the mould was thick. One contained a solution of arsenious acid, and the other contained arsenite of soda. These were at that time the only two bottles in my laboratory thus affected. I had a frog that died. I put it in the most concentrated solution-the arsenious acid. After a fortnight the mould was as thick as possible. The power of arsenic in killing the lower organisms is exceedingly weak. The effect of arsenic was, in my opinion, rightly described by Dr. Odell when he said that it acts upon the nerves. It is what might be called a stimulant, or rather tonic, by Dr. Atkinson, and in this way, by stimulating the nerves to greater activity, it exerts its influence.

Dr. WATT: Were the bottles uncorked?

Professor MAYR: Both were uncorked.

Dr. DARBY: We sometimes imagine we know the action of medicine, and yet we are all at sea about the action of arsenic when applied to the dental pulp. Some are of the opinion that it is absorbed,

while others are as strongly of the opinion that it acts by catalysis (by its presence). Dr. Flagg is on record as having said the following: "Then came the action of arsenic on the pulp. I placed a small portion of arsenious acid-one twenty-fifth of a grain-on a piece of cotton, mixed it with acetate of morphia, the whole being in turn mixed with creasote, placed it in a pulp-cavity, and devitalized that pulp. I made that same application to a number of teeth, and I left the cotton in each for two weeks, and in some, I think, for three weeks. Each one of those pulps I extracted from those teeth painlessly. It was a perfect devitalization of the pulp. They were taken out and held up before my patients, and they were told 'that is the pulp of your tooth,' and when I held this up and told them, every one of the ten said, 'is it possible that you have taken that from my tooth without my knowledge? If they did not know it, it could not have hurt them much. These pulps were then placed on paper, the terminal ends where the arsenic came in contact with them were cut off, and the remainder of the ten pulps analyzed in a bunch. They were treated by Reinsch's test for arsenic, which detects a two-hundred-and-fifty-thousandth of a grain. In the whole ten there could not have been the two-hundred-and-fiftythousandth of a grain, because there was not the ghost of a shadow of a show of arsenic. Now, if there was not the ghost of the shadow of a show in ten pulps, how much was there in one?" If I mistake not, that same piece of cotton with the twenty-fifth of a grain of arsenious acid was afterwards applied to the web of a frog's foot and it killed him as dead as a door-nail. I would not be understood as vouching for the correctness of this statement. It would be difficult to imagine so small a quantity of arsenic producing such wonderful results if it acted by absorption.

Dr. ATKINSON: Was the twenty-fifth of a grain not diminished in quantity? Did he weigh it afterwards?

Dr. DARBY: I don't know.

Dr. ATKINSON: That is the point.

Dr. BUCKINGHAM: I think I know something about that frog. I helped Dr. Flagg analyze it, or rather I analyzed it while Dr. Flagg looked on. Our tests were not very carefully made, but we found what we supposed to be arsenic in all parts of the frog. I did not see the other twenty-five cases in which arsenic had been applied to the mouth, but there was arsenic certainly absorbed and deposited through the whole system of the frog. I refused to indorse his paper, and the consequence was he went home and said he had re

peated his experiment, and published a paper over his own signature. I would not have anything to do with it. We do know that a very small quantity of arsenic will produce an effect, and although the twenty-fifth of a grain of arsenic will kill a dozen teeth, it does not follow that there is no arsenic absorbed, and we can explain this very easily, because when the pulp was killed the arsenic would be absorbed very little, there would be a cushion through which the arsenic would have to pass before it got into the other parts of the tissue. Arsenic may kill, and yet there may be an almost infinitesimal portion absorbed, but certainly arsenic must act some way rather than by its presence. I agree with Dr. Watt that there may be a chemical combination between the arsenic and the substance itself. Arsenic will act upon that which is weak, and it destroys the vitality in some way, but I don't know how it does it. When the quack doctors undertake to remove tumors with arsenic they apply it to the tissue that is weak or abnormal, and it will devitalize that tissue before it attacks the others. If it is applied to a healthy tissue it will be absorbed clear through, but if applied to diseased tissue it will probably destroy a portion of it, and that tissue becomes a cushion which prevents the absorption of the arsenic, and probably there will be a sloughing off. As to the minute action of the arsenic we have not a very clear idea, and we only know any of these things from experiment.

Dr. ALLPORT: The action of medicines is a very difficult thing to explain; from observation and experience we have learned to expect certain results from their administration; we know they act, but why they act we do not know. We know that we live, and we know that grass grows; we know that foods produce the growth of tissues but why we live, or why and how these growths are produced we do not know. Life and growth are the results of vital action in obedience to laws of the Infinite which are beyond man's comprehension. Observation and experience have taught us that by mixing an alkali and an acid, we get what chemists call a neutral, but just why we get this result, or why it was ordered that we do not get some other result is known only to Him who created the law. With reference to the action of arsenic in destroying the vitality of the tooth-pulp, and in regard to Dr. Flagg's experiments, I wish to say a word. I do this, not that I wish to fully indorse his conclusions, but because it seems to me that his ideas are not clearly understood here. I read what Dr. Flagg said on this subject many years ago, with a great deal of interest, and I will state what I remember

to be the substance of his experiments as well as the conclusions which he drew from them. He destroyed the vitality of a great many pulps by the use of arsenic, and at different times he collected numbers of them and applied the most delicate chemical and other tests to ascertain whether arsenic had been absorbed or not, and if absorbed, to what extent, and in what part of the tissue it existed. In these tests he found that the least possible amount had been taken up, and its presence was only detected at the point of contact of the drug with the tissue. From this he came to the conclusion that the death of the pulp was not so much from the absorption of the arsenic as from irritation by its presence. His conclusions were that irritation caused an increased flow of blood to the parts (which is always the case with irritation), and that the arteries became so much enlarged that they prevented a return of blood through the veins, and that death was caused by strangulation at the apex of the tooth. In my own practice I have found that much less arsenic is required to destroy an unwounded pulp than one where the pulp has been wounded. I have also found that in some cases by applying arsenic a portion of the pulp would slough off and the balance of the pulp would take on a healthy action and live for years. I doubt not that Dr. Atkinson and others who have paid particular attention to preserving the vitality of exposed pulps have met with the same results.

Dr. BUCKINGHAM: How does he explain how the arsenic got through the whole system of the frog?

Dr. ALLPORT: That he did not explain.