tracted with alcohol, and if this alcoholic extract be allowed to dry, and then be redissolved in a little water or salt solution and injected into the blood of a dog, the results which are obtained, considering the minute amount of substance added to the blood, are certainly most extraordinary. The nervous centre which regulates the action of the heart is powerfully affected, so that the heart either beats very slowly and weakly, or the auricles may even for a time stop beating altogether. If, however, these inhibitory influences be cut off by division of the vagi nerves, the effect of the poison upon the heart is of an opposite character. There is great accele ration of the rate of the beat and a great increase of force. This is accompanied by a strongly marked influence upon the blood-vessels, and especially upon the arterioles. The walls of these are chiefly muscular, and the drug exerts so powerful an action upon this muscular tissue as to cause the calibre of the vessels to be almost obliterated. The heart being thus increased in force and accelerated, and the calibre of the vessels almost obliterated, the result is to raise the pressure of the blood within the arterial system to an enormous extent, so that from a bloodpressure which would be sufficient to balance a column of some four inches of mercury the pressure may rise so high as to be equal to a column of mercury of twelve or more inches.

This result is obtained, as we have seen, by a very minute dose. We have to do here with a substance which is as potent, although in a different direction, as strychnia. Whether it is a useful substance formed by the supra-renals from materials furnished by the blood, and subsequently gradually used in the economy for the virtue of its action upon the circulatory system, or whether it is to be regarded as a poison, formed by the tissues during their activity and carried by the blood to the supra-renals, there to be rendered innocuous, we do not as yet certainly know. These are important points which must form the subject of further investigation. But, however this may be, it is clear that in this gland also we again meet with an instance of the physiological importance of what Sir Frederick Bramwell called the 'next to nothing.'

I will give one more instance, taken this time from a gland which is provided with a duct. Until quite recently it might have been thought that there was nothing very obscure regarding the functions of the pancreas. The pancreas is a digestive gland which lies below and behind the stomach: it has a duct which carries its secretion into the beginning of the intestine, and that secretion acts powerfully upon all constituents of the food, digesting starch, meat, and fat. It was not supposed that the pancreas had any other function to perform. Animals can live without this secretion, and to a large extent can continue to digest and absorb their food much as before; for it has been possible to divert the secretion from the intestine and to collect it at the surface of the body; and it is found under these circumstances that, although the food is not quite so readily digested, nevertheless the animal does not materially suffer from the lack of the secretion. It was discovered, however, a few years ago (by v. Mering and Minkowski) that if, instead of merely diverting its secretion, the pancreas is bodily removed, the metabolic processes of the organism, and especially the metabolism of carbohydrates, are entirely deranged, the result being the production of permanent diabetes. But if even a very small part of the gland is left within the body, the carbohydrate metabolism remains unaltered, and there is no diabetes. The small portion of the organ which has been allowed to remain (and which need not even be left in its proper place, but may be transplanted under the skin or elsewhere) is sufficient, by the exchanges which go on between it and the blood generally, to prevent those serious consequences to the composition of the blood and the general constitution of the body which result from the complete removal of this organ. Now, some years ago it was noticed by Kühne and Sheridan Lea that, besides its proper secreting structure composed of tubular alveoli, lined by granule-containing cells, there are highly vascular patches of peculiar epithelium-like cells scattered here and there in the substance of the pancreas, which are wholly unconnected with the ducts and, so far as one can judge, with the secretion of the gland. We do not know anything whatever about the function of these patches, although from their vascularity it is extremely probable that they are not without impor

tance physiologically, and it is tempting to conjecture that it is these cells which are specially concerned in effecting that influence upon the metabolism of carbohydrates which experiment has shown to be peculiar to the pancreas.

The lesson to be drawn from these results is clear. There is no organ of the body, however small, however seemingly unimportant, which we can presume to neglect; for it may be, as with the supra-renal capsules, the thyroid gland, and the pancreas, that the balance of assimilation and nutrition, upon the proper maintenance of which the health of the whole organism immediately depends, hinges upon the integrity of such obscure structures; and it is the maintenance of this balance which constitutes health-its disturbance, disease. Nor, on the other hand, dare we, as the investigation of the attraction-particle has shown, afford to disregard the most minute detail of structure of the body.

All is concenter'd in a life intense,

Where not a beam, nor air, nor leaf is lost,
But hath a part of being.'

The following Papers were read :—

1. On the Absorption of Poisons.

By Professor P. HEGER, Brussels.

2. On a New Theory of Hearing. By C. H. HURST, Ph.D.

3. On the Fats of the Liver. (A preliminary Communication.) By D. NOEL PATON.

It is pointed out that while the liver has been demonstrated to play an important part in the metabolism of carbohydrates and proteids, its possible connection with the metabolism of fats has not been investigated.

In the present series of observations an attempt is made to elucidate

A. The Source of Liver Fats.

I. Are they directly stored from the fat in the food?

a. Do they accumulate in the liver after a meal containing fats ?

b. Does the quantity of fats in the liver bear any proportion to the quantity of glycogen ?

II. Are they formed from the fats in the adipose tissue of the body?

a. Consideration of phosphorus poisoning.

b. Relative amount of fats in liver and adipose tissue during starvation. III. Are they formed during the katabolism of the protoplasm of liver cells? B. Fate of Liver Fats.

Before investigating these points certain preliminary observations were

necessary.

1. What is the best method of extracting the fats? Soxhlet's method was adopted.

2. How much of the ether extract is composed of true 'fats?' For saponification and estimation of the 'fatty acids' the method given by Hoppe Seyler, the method of Lebedeff, and the method of Kössel and Obermüller were tested. The last was found most satisfactory.

A large series of observations shows that the fatty acid in the ether extract varies much-from 40 to 70 per cent.-averaging about 65 per cent.

3. Is the proportion of fatty acids the same in the liver as in the ordinary fats of the body? Lebedeff's method was used. The solid acids (palmitic and stearic) are to oleic acid on an average as 1 to 15; in fishes, 1 to 35. This agrees with one or two previous estimations. In the fats of the body Lebedeff found in a lipoma 1 to 2:37, and in subcutaneous fat 1 to 5.11.

4. Is the distribution of fats uniform throughout the liver? It is found to be so.

5. In animals in the same condition is the percentage amount of fat in the liver nearly the same? Ten observations show that the variation is usually under 5 per cent., while the difference in the amount of fatty acids is even smaller.

A. The Source of Liver Fats.

I. Are they directly stored from the fat in the food?

a. The amount of fats in the liver at different periods after food was estimated, and, with the exception of a somewhat doubtful increase between twenty-four and thirty hours after the meal, no change in the amount of fat could be determined. Further experiments on this subject are being carried on.

b. Does the amount of fat bear any relationship to the amount of glycogen ? As a result of a large number of estimations it is concluded that the fats bear no relationship to the amount of glycogen.

II. Are they formed from the fats of the adipose tissue?

a. Much of the work already published on phosphorus poisoning tends to indicate that they are so formed.

b. During starvation the amount of fats in the body falls to a much greater extent than the liver fats, which undergo a comparatively small reduction.

III. Are they formed during the katabolism of liver protoplasm?

In the post-mortem liver kept for several hours at 40° C. no change in the amount of fats has so far been determined. Further experiments on this point are required.

B. The fate of the liver fats has not so far been sufficiently investigated to justify any conclusions.

4. On the Measurement of Simple Reaction Time for Sight, Hearing, and Touch. By Professor W. RUTHERFORD, M.D., F.R.S.

Reaction time is the interval that elapses between the stimulation of a sense organ and a motor response. The physiological process involved consists of (a) an afferent factor--the stimulation of a sensory terminal and transmission of an impulse along sensory nerve-fibres to the brain; (b) a psychical factor involving an act of sensory perception and the voluntary production of a motor impulse; (c) an efferent factor-the transmission of an impulse along motor nervefibres, and muscular contraction. To render the reaction 'simple,' discrimination is eliminated from the act of perception by repeating the same sensation again and again without variation in its character; and choice is eliminated from the voluntary act by giving the same motor response again and again. In the author's experiments motor response was given by the right forefinger closing an electrical key. The stimulus for sight was the movement of a flag attached to a lever; that for hearing was a click given by transmitting an induction shock through a telephone; that for touch was an induction shock or a mechanical tap. The reaction time was ascertained by recording the moments of stimulation and of response on a revolving cylinder and also on a pendulum myograph, and measuring the interval by a tuning-fork. The pendulum myograph has not hitherto been employed in such experiments. It is very advantageous in experimenting on hearing and touch. Successive curves are superimposed, so that variations in the time of successive reactions are visible at a glance, and can be readily measured. By photography the record can be readily printed or thrown on a screen for lecture demonstrations. The reaction times, as measured by the author's methods, differ considerably from those of some German observers. In observations made on eight intelligent healthy men, varying in age from nineteen to sixty-two, the reaction time for sight varied from 0·1662 second to 0.2202 second, and was mostly between 0.20 second and 0.22 second. The reaction time for hearing varied from 0.1448 second to 01930 second, and was mostly betwee""* 0.15 second and 0.16 second. The reaction time for touch varied from 0.14

second to 0.1906 second in the different cases. The shortest touch reaction time is that following stimulation of the cheek: it varied from 0·141 second to 0.157 second. When the skin of a finger was stimulated the reaction time varied from 0.142 second to 0.190 second, but was mostly from 0-15 second to 0-18 second in the different cases; there was no evident relation between age and length of reaction time in the cases under observation. In a limb the reaction time is generally longer the greater the length of sensory nerve traversed by the impulse; but there may be considerable variations in the reaction times for different districts in the field of touch not explicable by difference in the length of sensory nerve traversed, but probably due to difference in the closeness of relation between centres for tactile sense in the brain and the motor centre for the hand. It may therefore happen that a response is given sooner by the hand when its skin is stimulated than when the mucous membrane of the tongue is stimulated, although in the latter case the impulse has a much shorter tract of sensory nerve to traverse. When the right hand gives the response the shortest reaction times for hearing and touch are obtained by stimulating the right ear and right side of cheek. In the experiments on sight both eyes were used at the same time. The influence of fatigue on reaction time and the remarkable restorative effect of tea were demonstrated in the photographs.

5. On the Microscopic Appearance of Striped Muscle in Rest and in Contraction. By Professor W. RUTHERFORD, M.D., F.R.S.

6. On Effects of Suprarenal Extract. By Professor E. A. SCHÄFER, F.R.S.

7. On Epithelial Changes produced by Irritation. By D'ARCY POWER, M.A., M.B. Oxon., F.R.C.S., Lecturer on Histology at the Royal Veterinary College.

Mr. Power showed a series of preparations of the conjunctival and vaginal mucous membranes taken from rabbits and guinea-pigs which had been subjected to mechanical and chemical irritation. Many of the epithelial cells presented appearances which were identical with those described as being parasitic when they were met with in cancer. The changes in the epithelium were summarised as a general vacuolation of cells; various forms of intracellular oedema; epithelial 'pearls,' collections of leucocytes, and the spaces left after these leucocytes had migrated. These changes he had already described and figured in the British Medical Journal' for 1893. The series of preparations shown on the present occasion indicated that many squamous epithelial cells had the power of phagocytosis, for in no other way could the remarkable intracellular appearances be explained, and he showed cells containing a leucocyte, and others containing a microcyte. Partial necrosis of the cell also took place as a result of irritation, and there was an invasion of large eosinophile cells into the conjunctival epi

thelium.

The full text of the paper, with illustrations, is published in the 'Journal of Pathology and Bacteriology' for October 1894.

SATURDAY, AUGUST 11.

The following Papers were read :

1. On Vowel and Consonant Sounds. By D. L. HERMANN, Professor of Physiology in the University of Königsberg.

2. On an Aerotonometer and a Gas-burette.'

By Professor LÉON FREDERICQ, Liège.

The air which enters the lung is rich in oxygen (20.9 per cent.) and poor in carbonic acid (0-03 per cent.). On leaving the lung it is relatively poor in oxygen (18 per cent. in dogs) and rich in carbonic acid (2 to 3 per cent. in dogs). It has given up oxygen to the blood and received from it carbonic acid.

What is the cause of this gaseous exchange between the blood and the air of the pulmonary alveoli? Pflüger believed that he had succeeded in explaining this exchange by the simple laws of gaseous diffusion-laws in virtue of which each gas passes from a medium in which its tension is high towards a medium in which its tension is low. The determinations of carbonic acid tension made by Pflüger's pupils simultaneously in the blood by means of the aerotonometer and in the air of the pulmonary alveoli were in complete harmony with this explanation. Christian Bohr has come to a different conclusion on this subject. According to him, gaseous diffusion alone does not explain the exchange of gases between the blood and the air of the lung. Bohr has found in several of his experiments the air of the alveoli richer in oxygen and poorer in carbonic acid than in the arterial blood leaving the lung. According to Bohr, the tissue of the lung plays an active part in respiration: the pulmonary epithelium excretes carbonic acid by a true secretion process, and passes oxygen into the blood, not in accordance with the laws of diffusion, but against these laws.

I have recently taken up this subject again, and in doing so have made use of the aerotonometer exhibited to the Section, which is a modification of the instrument of Pflüger. The apparatus consists essentially of a sufficiently long vertical tube, connected above with the carotid of a living animal (an anæsthetised dog), and below with a vein. The arterial blood (which has previously been rendered incoagulable by the injection of propeptone) flows continuously over the inner surface of the tube of the aerotonometer, which is kept at a temperature of 38° C. If the experiment lasts sufficient time for the attainment of equality of tension of the gases of the blood and those enclosed in the aerotonometer, an analysis of the latter gases will indicate the tension of the gases of the blood. Bohr believed that equality of tension could be reached in a few minutes, and thus obtained erroneous results. I have found that nearly two hours are necessary before equality of tension is reached. One finds then that the air of the aerotonometer contains 2 to 3 per cent. of carbonic acid and 12 to 14 per cent. of oxygen, representing the tension of these gases in the blood in accordance with the diffusion theory. I have also found that if one lets the animal breathe pure or nearly pure oxygen, the tension of this gas in the arterial blood may exceed 60 per cent. of an atmosphere. The animal, nevertheless, shows only a slight tendency to apnoea; it continues to breathe. Apnoea is thus not a necessary result of a very high oxygen tension in arterial blood. This is a fact which seems to me very important in connection with the theory of apnoea.

The gas analyses were made with a gas-burette, shown to the Section, which is simply a modification of that of Hempel. The burette is drawn out at the level where the readings are made, so as to permit of reading easily to 02 or 01 c.c. The confining liquid is water (and not mercury), which gives rise to scarcely any error, diffusion of gases into liquids being so slow. The carbonic acid is absorbed by potash solution, the oxygen by phosphorus.

3. On Local Immunity. (A Preliminary Communication.)? By LOUIS COBBETT, M.A., M.B., F.R.C.S., and W. S. MELSOME, M.A., M.D, If it be true, as there seems reason to believe, that recovery from an infectious disease is due to certain changes in the body, which make it more resistant to the micro-organisms which cause that disease, and that the same changes are also the

For further details see Centralblatt für Physiologie, 1893, vii. p. 26; 1894, viii. p. 34. 2 A full report is published in the Journal of Pathology, 1894.