648 



PHYSIOLOGY. 



intestine, MacFayden, Nencki, and Sieber found 

 that the duration of the passage of food from 

 the mouth to the ileo-cascal valve was- two hours 

 at the earliest, and the food of one meal con- 

 tinued to pass for from nine to fourteen hours. 

 The food consisted of bread, meat, peptones, 

 oatmeal, milk, eggs, sugar, and beef tea. The 

 chyme as obtained from the end of the small 

 intestine contained dissolved coagulable albu- 

 mens, mucin, peptones, dextrin, sugar, inac- 

 tive fermentescible and optically active paralac- 

 tic acid, volatile fatty acids, especially acetic acid, 

 the biliary acids, and bilirubin. The acid reaction 

 of the chyme was always due to the presence of 

 organic acids. Neither indol, skatol, phenol, 

 leucin, nor tyrosin was present, the fact showing 

 that in this case at least the albumen was hardly 

 touched by microbes in the small intestine, while 

 the carbohydrates were decomposed with forma- 

 tions of acid. 



In a research on ferment actions of the pan- 

 creas in different animals, Vincent D. Harris and 

 William J. Gow sought to obtain information 

 upon the following points : 1. Whether the fer- 

 ments with the possession of which the pancreas 

 is usually credited are present in the pancreas of 

 animals of different classes, and, if so, whether 

 there is any marked difference to be discovered 

 in the activity (or amount) of each ferment in 

 each class. 2. Whether the activity or amount 

 of the ferment bears any relation to the food of 

 the animal. 3. Whether the ferments of the 

 human pancreas are markedly affected in activ- 

 ity or amount in morbid conditions of the body ; 

 and whether, in addition to the generally accepted 

 pancreatic ferments, the gland possesses any 

 additional ferment action (a) in inverting cane 

 sugar, or (b) in producing any chemical action 

 upon dry or unboiled starch. It had been estab- 

 lished from previous observations that very defi- 

 nite ferments exist in pancreatic juice, and 

 may be extracted from the gland by means of 

 glycerin and other vehicles ; that these ferments 

 have special relations to the different classes of 

 food stuffs ; and that during secretion the fer- 

 ments which had been previously deposited 

 within the pancreatic cells in granular and unde- 

 veloped form are discharged into the lumen of 

 the tubes. The purpose of the authors in their 

 investigation was to inquire whether the fer- 

 ments, four in number, which the pancreas is 

 said to possess, appear in the gland of all ani- 

 mals. It appears from the researches under the 

 first head, that of the four ferments dealt with 

 the tryptic ferment is by far the most universal 

 and hardy ; next to it is put the rennet ferment ; 

 next the diastatic ; and, lastly, as being that 

 which is, if present universally in the pancreas 

 of animals (which the authors are strongly in- 

 clined to doubt), most easily destroyed by pre- 

 serving the pancreas in spirit, the fat-splitting 

 ferment. No proof was found of any special fat- 

 emulsifying ferment. Concerning the second 

 question, the experiments show that the pancre- 

 ases of the carnivorous animals the lion, leop- 

 ard, serval, and ocelot have little or no power 

 of converting starch into sugar, do not possess 

 any rennet ferment, and that their tfyptic 

 power was unusually active. In the extracts of 

 the pancreases of several other carnivorous ani- 

 mals the diastatic power was slight, while the 



horse's pancreas gave an irregular result, was in- 

 active in amylolytic power, and was very active 

 in regard to its tryptic or proteolytic ferment. 

 The tryptic ferments of several carnivorous ani- 

 mals was only slightly active. The fat-splitting 

 ferment was not present in pancreatic extracts. 

 The rennet ferment was more often present than 

 not, and in some pancreases was extremely 

 powerful. The pig, the ox, man, and the sea 

 eagle appear in the first class as regards the 

 activity of all their ferments. The cases experi- 

 mented upon under the third of the queries were 

 too few to justify definite conclusions ; but three 

 of them indicated that the activity of the hu- 

 man pancreatic ferments may be considerably 

 diminished in wasting disease. Under the fourth 

 question, it appeared that neither active brine ex- 

 tracts of pancreas nor fresh pig's pancreas have 

 the power of inverting cane sugar in an active 

 medium, and that fresh pig's pancreas has the 

 power of converting raw starch into dextrin. 

 Experiments with reference to different fer- 

 ments proved that antiseptics do not interfere 

 with the action of the unorganized ferments, 

 and confirm the results of former experiments 

 by Harris and Tooth. 



Experiments were recently made by Herr Ro- 

 senberg with a dog, in the inquiry whether the 

 process of digestion is promoted or hindered by 

 bodily exertion. The animal was fed daily with 

 a fixed average ration, and the amount of nitro- 

 gen and fat daily absorbed was duly determined. 

 Five series of experiments were made, each in- 

 cluding a rest period followed by a working 

 period, in which the dog was made to work on a 

 treadmill. In some cases the efforts were made 

 during stomachic, in others during intestinal 

 digestion. In both series of experiments the 

 differences observed lay within the limits of 

 physiological variations, and the inference was 

 drawn that, in a healthy dog, the utilization of 

 food is independent of the condition whether the 

 dog rests or is energetically at work during di- 

 gestion. 



Nervous System. In whatever way, says 

 Richard E. Edes, we may picture to ourselves 

 the process going on in a nerve fiber while trans- 

 mitting an impulse, it must come under one of 

 two heads : It must be either a " chemical " 

 process, comparable to a train of gunpowder, in 

 which we may suppose the decomposition in one 

 part to start decomposition in the neighboring 



Eart, and so on ; or a physical process, compara- 

 le to the vibration of a stretched wire, or the 

 propagation of sound waves in a flexible tube. 

 On the first hypothesis three things must take 

 place: (a) Change in the chemical composition of 

 the transmitting matter, as revealed by chemical 

 tests ; (b) production of heat ; (c) using up of 

 potentially energetic material with production 

 of waste or unenergetic material, causing phe- 

 nomena of fatigue. The experiments of Mr. 

 Edes with reference to the determination of these 

 points, performed in the laboratory of the Har- 

 vard Medical School, as reviewed by him, are to 

 be divided into two parts : First, those on ex- 

 hattstibility, which depend for their value on the 

 positive proof of activity after long periods of 

 stimulation, and thus offer positive evidence ; 

 and, second, those on heat production and chem- 

 ical changes recognized by chemical methods, of 



