142 



In recent 3'^ears much attention has been directed to the study of the 

 chemical structure of proteids of animal and vegetable origin, espe- 

 ciall}^ as shown by the number and nature of the cleavage products 

 obtained ])y the action of difi'erent reagents. In this connection the 

 animal proteids arc of especial interest. They have been found to vary 

 verv greatly in complexity from scombrin, obtained from the repro- 

 ductive organs of mackerel, which, according to Kossel and Dakin,<* 

 yields only three or four cleavage products, to such bodies as casein, 

 globin, etc. According to E. Fischer's'' investigations, casein yields 

 16 cleavage products and in globin, a body isolated from the oxyhemo- 

 globin of horse blood, Abderhalden ^' has identified 1-1 cleavage prod- 

 ucts. Some of the proteids studied are of importance from tlie stand- 

 point of nutrition, while others are not of so great interest in this 

 connection; but as a whole such studies are of undoubted value because 

 of the data they provide regarding the chemical nature of nitrogenous 

 foods, and it is fortunate that so many chemists are turning their 

 attention to these problems. 



In their study of the relative merits of white and red meat in 

 invalid dietetics. Offer and Rosenquist"^ determined the total nitrogen, 

 nitrogen of extractives, and nitrogen of meat bases in a large number 

 of samples of tish, poultry, veal, pork, beef, mutton, venison, and 

 salted and smoked meats. In some cases analyses were made with 

 cooked samples, but in most cases with the raw meat. The smallest 

 proportion of total nitrogen, 2.54 per cent, was reported in a sample 

 of pork; the highest, 4.09 percent, in dried beef. The majority of 

 the samples contained from 0.4 to 0.5 per cent nitrogen of extractives. 

 Less than 0.4 per cent was noted in samples of boiled beef (soup meat), 

 fillet of beef, pork, and chicken, and over 0.5 per cent in pike, perch, 

 scraped beef, and raw and cooked ham. In the case of nitrogen of 

 meat bases the largest proportions, 0.071, 0.056, and 0.05 per cent, 

 Avere reported in scraped beef, pork, and boiled beef (soup meat), 

 respectively, and the smallest proportions, 0.009 and 0.007 per cent, 

 respectively, in venison and pike. 



E. Zunz' studied some of the constituents of veal. When 5 kilo- 

 grams of lean veal, taken three-quarters of an hour after the calf was 

 slaughtered, was boiled, 0.679 gram histidin, 0.138 gram arginin, 0.559 

 gram lysin, 0.227 gram leucin, 0,662 gram glutaminic acid, and 0.371 

 gram aspartic acid were recovered. 



«Ztschr. Physiol. Chem., 44 (1905), p. 842. See also Kossel, Ibid., p. 347. 

 '^Ztsrhr. Physiol. Chem., 33 (1901), p. 151. 

 <-Ztschr. Physiol. Chem., 37 (1903), p. 499. 

 '? Berlin. Klin. Wchnschr., 3G (1899), pp. 937, 968, 1086. 



« Ann. Soc. Roy. Sci. Med. et Nat. Bruxelles, 13 (1904); abs. in Zentbh Physiol., 

 18 (1904), p.' 852. 



