PHYSIOLOGY. 



693 



itself painfully, and increased peristaltic action 

 had set in, the respiratory interchange was 

 " again determined. In all cases the gaseous in- 

 terchange was increased by from 7 to 30 per 

 cent, more than the normal. The several per- 

 sons behaved very differently in this respect, 

 and the same person showed marked differ- 

 ences in the increase of respiratory interchange 

 at different times, after equal doses of salt. As 

 a rule, the increase was proportional to the 

 amount of discomfort experienced by the pa- 

 tient in the lower parts of the body. 



Dr. Marcer, in the investigation of normal 

 respiration, directs attention to the occlusion of 

 a proportion of the air inspired, and insists on 

 the importance of considering the proportion 

 of it to the carbonic acid expired. 



Digestive System. Later studies by Dr. J. X. 

 Langley on the physiology of the salivary se- 

 cretion relate to the effect" of atropine upon the 

 supposed varieties of secretory nerve-fibers. 

 Heidenhain supposes that there are two kinds 

 of secretory fibers, one proper secretory caus- 

 ing a flow of liquid, and the other trophic caus- 

 ing an increase in solubility in the stored-up 

 gland substance. The author had already 

 shown that on the assumption of the existence 

 of different kinds of secretory fibers, there is 

 ground for supposing that there is a third va- 

 riety anabolic fibers causing the formation 

 of fresh substance by the cells. The effects of 

 atropine having been observed only on the 

 proper secretory fibers, Dr. Langley's observa- 

 tions were extended to the other fibers, with 

 the result that the drug was found to paralyze 

 the trophic, anabolic, and secretory fibers si- 

 multaneously. Hence, the author concludes, 

 the various changes caused in the gland cells 

 by nerve stimulation are all affected by atro- 

 pine, and to approximately equal extents. 

 When paralysis of the chorda occurs, it is a 

 paralysis of the whole of its function with re- 

 gard to the gland-cells. In other words, the 

 phenomena of atropine poisoning give no indi- 

 cation of the existence of more than one kind 

 of secretory nerve-fiber in the chorda tympani. 



G. Sticker concludes, from his observations, 

 among which were special experiments upon 

 living persons, that the supposition that the 

 salivary secretion plays no part in gastric di- 

 gestion is erroneous ; and that, on the contrary, 

 the presence of saliva in the stomach has a 

 direct effect in promoting the secretion of gas- 

 tric juice. 



Dr. Poulet has found evidence that the acid 

 of the gastric juice in man, as ascertained by 

 the process of dialysis during the first period 

 of digestion, is exclusively the hippuric, while 

 during the close of digestion there is a mixture 

 of hippnric and tartaric acids. In the fasting 

 state tartaric acid is alone present. 



In experiments to determine the effect of 

 cooking on the digestibility of starchy foods, 

 Dr. X. Butiagin. of St. Petersburg, found that 

 the activity of the saliva does not differ much 

 among healthy persons, but that when people 



are badly nourished and weak, and especially 

 when they are also suffering from disease, their 

 saliva has a diminished power of dissolving 

 starch, When starchy substances are subjected 

 to prolonged cooking they become more easily 

 digestible ; and in this way compensation may 

 be provided for the inactivity cf the saliva of 

 weakly persons. Thus, rice find peas were 

 found to require three hours' cooking in order 

 to render them as easily digested in the saliva, 

 possessing only 88 per cent, of the normal ac- 

 tivity, of a badly nourished, hysterical woman, 

 as they were with a single hour's cooking by 

 the saliva of healthy persons ; and generally it 

 was found that in the case of weakly or dis- 

 eased persons starchy food must be cooked 

 twice or thrice as long, in order that it may be 

 equally acted upon, as in the case of healthy 

 persons. Again, when starch has been cooked 

 for a long time there is less difference bet-ween 

 the effects of healthy and unhealthy saliva 

 upon it ; this is especially remarkable in the 

 case of millet, which after one hour's cooking 

 showed a difference of 12-89 per cent, in favor 

 of the saliva of healthy as against that of dis- 

 eased persons, but after three hours' cooking a 

 difference of only 5'77 per cent. 



From a series of experiments still going on, 

 Drs. Vincent D. Harris and Howard H. Tooth 

 have obtained evidence in support of the gen- 

 erally accepted belief that micro-organisms 

 need not take any part in gastric digestion. 

 In regard to the formation of leucin and tyro- 

 sin in pancreatic digestions, although their ex- 

 periments were inconclusive, they have been 

 led to believe that the formation of these sub- 

 stances depends, in part at all events, on bac- 

 teria. It seems to them likely that the forma- 

 tion of indol and its allies in the alimentary 

 canal below the stomach is a mode of excreting 

 nitrogen, like the production of lencin and ty- 

 rosin, and that the former substances are not 

 formed from the latter, but directly from pep- 

 tone. 



The researches of Drs. Henry Leffmann and 

 William Beam on the action of antiseptics in 

 perishable articles of food upon the organism 

 and their effect on the nutritive or medicinal 

 value of any articles with which they may be 

 associated were based on the estimation of the 

 sugar formed in presence of a large excess of 

 starch, arrow-root starch being selected for the 

 purpose of the experiments. It was found that 

 salicylic acid prevents the conversion of starch 

 into sugar under the influence of either diastase 

 or pancreatic extract, but does not seriously in- 

 terfere with peptic or pancreatic digestion of 

 albumen. Saccharin holds about the same re- 

 lation as salicylic acid. Sodium acid, sulphite, 

 and boric acid are practically without retard- 

 ing effect. Beta-naphthol interferes decidedly 

 with the formation of sugar by diastase, but 

 not with the action of pancreatic extract on 

 starch. Peptic and pancreatic digestions of 

 albuminoids were almost prevented by this 

 agent. The authors conclude that the indis- 



