The Orgnvism and its Chemisiry 103 



There has been some question whether these are true 

 proteids, but at any rate they seem to be relatively simple 

 and definite in composition so tliat Kossel has regarded 

 them as the foundation of the protein bodies. It has been 

 possible to work out probable empirical formulae for them, 

 and herein their natural history significance comes strikingly 

 to view. The formula C32H54N18O4 was assigned by Miescher 

 to tlie protamine of Salmon sperm, the substance being 

 proved to contain the nucleic acid radical. The comparative 

 studies of Kossel and his students extended to the spenn 

 of the herring, mackerel, sturgeon, and perch, and brought 

 out the fact that while the nucleic acid part of the molecule 

 is the same for the different genera, the basic part is dif- 

 ferent in each, so a name is required for the protamine de- 

 rived from each kind of fish. The names salmme, clupeme, 

 scombrine, sturme, cyprimne, cyclopterine^ etc., proposed 

 by Kossel have consequently come into general use. These 

 differ in formulae. Thus Kossel gives clupine as C30HC2N14 

 Oo and sturine as C36H69N19O7. They also differ in the 

 cleavage products yielded, histidine for example, being ex- 

 tracted from sturine and from none of the others, and tyr- 

 rosine from cyclopterine exclusively. All, on the other 

 hand, yield arginine while lycine was found only in sturine 

 and cyprinine, and so on. 



(d) Comparative Chemistry of Milk From Different Species 



The milk of several species of mammals has been ex- 

 tensively investigated mostly from physiological and dietetic 

 standpoints, but the difference between the milks of dif- 

 ferent groups has come out with positiveness. It seems that 

 on the whole the milks of carnivorous species are more alike, 

 and those of herbivorous species are more alike, than tliose 

 of either of these categories are like those of the other, but 

 there are not enough observations to warrant laying this 



