g6 SCIENCE PROGRESS. 



marsten on human bile {Konigl, Gesellsch. der Wissensch., 

 Upsala, June, 1893), m addition to numerous analyses, the 

 statement is made that the mucin is true mucin, not nucleo- 

 albumin as in ox-bile. Chitin has been the subject of two 

 papers by N. P. Krawkow ; he points out [Central. Med. 

 IViss., 1892, 145) that this substance gives a reaction with 

 iodine like the albuminoid material found in waxy degenera- 

 tion : he further [Zeit. Biol., xxix. 1 17) from an examination 

 of various invertebrate skeletons states that several varieties 

 of chitin exist. 



Nutrition.- -This wide term includes the subjects of 

 digestion of foods, and their value in o-eneral metabolism. 

 Under the first head, the papers of Kuhne and Chittenden 

 on peptones and Hammarsten on bile have been already 

 mentioned in preceding paragraphs. In addition to these 

 there are other papers of which the most important are 

 the following : On pancreatic juice in different animals, by 

 Harris and Gow [Jour. Physiol., xiii. 469). The tryptic 

 ferment was found most constantly present, then the ren- 

 netic, then the diastatic ; the fat-splitting ferment was often 

 absent, and no special fat-emulsifying agent was ever found. 

 On hydrolytic ferments, by H. Hildebrandt (Virchow's 

 Archiv, cxxxi. 5) ; this relates chiefly to the toxic effects 

 of, and fate in the body after subcutaneous injection of rennin, 

 emulsin, and invertin. A certain amount of immunity is 

 brought about by the administration of successive very 

 small doses of these agents. On putrefaction in the 

 intestines, by C. Schmitz [Zeit. physiol. Client., xvii. 401). 

 Here it is shown that milk lessens putrefaction, as evi- 

 denced by the fall of ethereal sulphates in the urine ; 

 casein not lactose is probably the antiseptic agent. Hydro- 

 chloric acid in man but not in dogs acts in the same way. 

 On the acids of ox-bile, by Lassar-Cohn [ibid., xvii. 617); 

 this gives quantitative analyses. 



The papers on general metabolism are more numerous. 

 H. Hildebrandt [ibid., xviii. 180) confirms with careful 

 experiments the already well-known fact that albumoses 

 have a high nutritive value. E. Krauss [ibid., xviii. 167) 

 points out that, in calculating the value of nitrogenous 



