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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.

necessary.

Before investigating these points certain preliminary observations were 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, I 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 between 0.15 second and 0.16 second. The reaction time for touch varied from 0-1416

second to 0.1906 second in the different cases. The shortest touch reaction time is that following stimulation of the cheek: it varied from 0141 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 cedema; 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 epithelium.

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 di Physiology in the University of Königsberg.

2. On an Aerotonometer and a Gas-burette.1

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.

cause of subsequent immunity, the well-known fact that in erysipelas the parts first attacked may be recovering while the disease is spreading elsewhere would lead us to suspect that these parts have learnt to resist the streptococcus while the rest of the body is still susceptible.

To inquire whether erysipelas confers any such local immunity was the object of the following experiments:

Fourteen rabbits which had recently suffered from erysipelas in the right ears were again inoculated with the streptococcus, this time in both ears. In each case a control animal, inoculated at the same time, suffered from typical erysipelas. The results were as follows: Left ears.-In four, only a little redness about the seat of inoculation. In four, erysipelas commenced, but aborted on the third or fourth day. In six, typical erysipelas. Right ears.—Inflammation rapidly appeared, affected the whole part, and subsided in twenty-four to forty-eight hours. Culture experiments, which invariably revealed the presence of streptococci in the early stages of true erysipelas, showed that micro-organisms were absent from the inflamed right ears. Thus all the right ears showed themselves to be immune, while nearly one half the left ears proved as susceptible as those of the control animals. Hence we conclude that the first attack of erysipelas had conferred a very complete local immunity. That erysipelas confers some degree of general immunity is already well known from the work of Fehleisen, Roger, and others.

Further experiments showed that this local immunity lasted only so long as any thickening remained in the ears after erysipelas. Its duration depended, therefore, on the severity of the first attack.

The inflammation which resulted from inoculations of ears previously affected we thought to be a reaction against the poisons actually introduced, and not due to the vital activity of the cocci, because we could obtain no evidence that these had multiplied and invaded the ear. This opinion was put to the test by injecting into both ears of animals, which had recently suffered from erysipelas in one ear, small quantities of concentrated filtered cultures, and in one case the streptococci themselves destroyed by heat. In these experiments a somewhat violent inflammation, of short duration (two to three days), resulted in the right ears, and a less severe but more prolonged inflammation in the left. An important difference was in the time of onset of this inflammation, which in the previously affected ears appeared many hours earlier than in the others; a difference similar to that which had already been observed to result from the inoculation of living cocci under the same conditions. Thus it appears that parts which have recently suffered from erysipelas become more quickly and intensely inflamed when subjected to the action of the products of the streptococcus than do other parts of the same animal. And when we remember that this tendency to inflammation goes hand in hand with a notably greater resistance to the living microbe, we are led to regard it as beneficial in its action, and an important factor of local immunity; an opinion in harmony with that already expressed by Metchnikoff and others-viz. that inflammation is a protective process.

4. A Form of Experimentally-produced Immunity.

By J. LORRAIN SMITH, M.A., M.D., and E. TREVITHICK, M.B. The occurrence of fibroid changes in the lungs when these are due to the irritant effect of inhaled dust is, according to clinical authorities, associated with increased liability of the lungs to infection by the tubercle bacillus. On the other hand, there is much clinical as well as experimental evidence to show that the condition of inflammation in the tissues is in general accompanied by an increased power of resisting the invasion of microbes.

The following experiments are brought forward to show that, in its early stages, the inflammation due to irritating dust in the pleural cavity increases the difficulty of infecting the animal in this locality with the bacillus pyocyaneus. The experiments were made on guinea-pigs and rabbits.

The dust (pounded glass) was placed in a bottle containing a quantity of water. This was sterilised, and before injection the dust was stirred up and mixed

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