738 



PHYSIOLOGY. 



is a potent drug, and as such may exert at 

 times some specific action upon metabolic 

 changes. Alcohol may then be considered as 

 having the power to diminish somewhat the 

 metabolism of proteid matter, and thus to con- 

 serve the tissues a power which is dependent 

 mainly upon its character as a non-nitrogenous 

 food. At the same time, it has some specific 

 action upon nutrition, as is manifested in its ten- 

 dency to increase the excretion of uric acid. 



From experiments made upon himself, Dr. 

 Eiehenberg found that a small dose of strong 

 alcohol, as in brandy, shortens the time that food 

 in general whether animal or vegetable, or a 

 mixture remains in the stomach by more than 

 half an hour. A similar but not quite so marked 

 effect is produced by a dose of dilute hydro- 

 chloric acid or mustard. Pepper and cundu- 

 rango diminish the time the food remains in the 

 stomach by about a quarter of an hour. Beer 

 and an infusion of rhubarb had no effect. 



The nature and composition of the peptone 

 formed by the action of typsin on myosin, and 

 the character of the residue of insoluble matter 

 which is found after the digestion of myosin with 

 pancreatic juice, have been studied by R. H. Chit- 

 tenden and Ralph Goodwin. The authors found 

 in myosin- peptone another illustration of the 

 fact that peptones differ widely from the mother 

 proteid in containing a much lower percentage 

 of carbon a fact which they regard as favorable 

 to the view that the formation of peptone is the 

 result of a process of hydration. 



An opportunity has been enjoyed by Drs. 

 MacFadyen. Nencki, and Sieber of studying the 

 chemical processes of the small intestine in a 

 patient who had an intestinal fistula. The false 

 anus was situated in the ileum just above the 

 ileo-caecal valve, so that the materials escaping 

 thereby were wholly composed of the chyme 

 which had passed through the whole length of 

 the small intestine. The patient continuing in 

 this condition for six months, a long series of 

 observations could be made relative to the time 

 and character of internal digestion under vary- 

 ing 'forms of diet, etc. The material, or chyme, 

 if it might be so termed, that escaped from the 

 fistulous outlet was more fluid and diarrhoeal 

 when the diet was albuminous than when it was 

 mainly of a vegetable nature. The flow from 

 the small into the large intestine was steadily 

 continuous, but less marked during the night, 

 when no food was taken ; and by some ingeni- 

 ous experiments it was shown that the passage 

 of foods from the mouth to the caecum occupies 

 at the least two hours ; but the traces of the 

 substances introduced did not disappear wholly 

 for from nine to fourteen or even twenty-three 

 hours. The fact was brought out that albumen is 

 hardly, if at all, decomposed in the small intes- 

 tine. Even the action of the trypsin of the pan- 

 creatic juice is small. The bacteria of the small 

 intestine are concerned in the disintegration of 

 the carbohydrates into lactic, acetic, and succinic 

 acids, and into ethylic alcohol. While it is gener- 

 ally believed that the chyme is rendered alkaline 

 by the secretion of the small intestine, the au- 

 thors found the total quantity of acid to be more 

 than could be neutralized by the bile, pancreatic, 

 and intestinal juices. 



During his experiments on emulsions, B. K. 



Rachford found that heating neutral olive oil 

 developed fatty acid and made it emulsible, and 

 that if this heated oil was again neutralized it 

 became non-emulsible, thus showing the emulsi- 

 bility to be due to the acidity. The results of 

 experiments with this and w'ith castor oil indi- 

 cated that the fatty acids of an oil are the fatty 

 acids best adapted for giving emulsibility to 

 this particular oil. The splitting of fats is a 

 most important preliminary step in fat diges- 

 tion. That the cooking of fats will develop in 

 them a fatty acid is therefore a fact of consid- 

 erable physiological importance, and one that, 

 so far as the author knows, has not previously 

 been noticed. It is his belief that the chemical 

 force developed by soap formation is the chief 

 factor in the formation of all physiological 

 emulsions. 



The changes produced in casein by the action 

 of pancreatic and rennet extracts have been in- 

 vestigated by J. Sydney Edkins, who mentions 

 among the facts which he has determined that 

 there exists in pancreatic extracts a ferment 

 which has the power of causing some alteration 

 of casein to occur, apart from proteolytic 

 changes, and this is manifested in appropriate 

 conditions by the clotting of milk or casein 

 solution. This ferment can be differentiated to 

 some extent from the proteolytic ferment, and 

 then appears to be a ferment comparable to the 

 rennet ferment of gastric extracts. With active 

 pancreatic extracts the proteolytic ferment has 

 such power that the altered casein exists but a 

 short time before it is further changed. The 

 addition of neutral salts will result in the clot- 

 ting of milk under the influence of pancreatic 

 extracts, when otherwise no apparent tendency 

 to clot existed. This can not be referred to the 

 retarding influence of such salts upon the pro- 

 teolytic ferment. When no change apparent to 

 the naked eye has occurred in milk as the result 

 of the action of pancreatic extracts, a clumge 

 may be shown to have occurred by the applica- 

 tion of heat, by the addition of an 'equal bulk of 

 saturated solution of sodium chloride, or by the 

 addition of exact quantities of acid. The same 

 changes occur in milk when treated with mini- 

 mal quantities of rennet ferment, in such amount 

 as to produce no actual clotting. This changed 

 casein, or metacasein, as it has been termed by 

 Roberts, may be separated by the addition of 

 sodium chloride, and purified. A solution of 

 this metacasein does not clot when subjected to 

 the action of rennet. The properties of this 

 metacasein indicate that it is closely allied to 

 tyrein. 



Nervous Systeui. In his successive publica- 

 tions on sleep and its causes, Dr. James Capj ie 

 accepts the position usiially taken by physiol- 

 ogists, that the state of sleep is accompanied by 

 a diminished brain circulation, but contests the 

 view that it is due to a diminution of the whole 

 mass of blood within the cranial cavity, and 

 that the compensation for this diminution is got 

 by an increase in the amount of cerebro-spnial 

 fluid in the ventricular and sub-arachnoid spaces 

 of the brain. He believes that, lying within a 

 closed cavity possessing rigid bony walls, the 

 brain can not be affected directly by the press- 

 ure of the atmosphere ; and that this can influ- 

 ence the interior of the cranium only through 



