BLOOD RELATIONSHIP 309 



Biological Classification and Organic Evolution: The 

 Crystallography of Hemoglobins," by Edward Tyson 

 Reichert and Amos Peaslee Brown (published by the 

 Carnegie Institution of Washington, 1909). 



The following extracts give the deductions from an 

 immense amount of painstaking and difficult experi- 

 ment and investigation: 



"The authors feel that "The trend of modern biological science 

 seems to be irresistibly toward the explanation of all vital phe- 

 nomena on a physico-chemical basis." " The striking parallelisms 

 that have been shown to exist in the properties and reactions of 

 colloidal and crystalloidal matter in vitro and in the living organ- 

 ism lead to the assumption that protoplasm may be looked upon 

 as consisting of an extremely complex solution of interacting and 

 interpendent colloids and crystalloids, and therefore that the 

 phenomena of life are manifestations of colloidal and crystalloidal 

 interactions of a peculiarly organized solution. We imagine this 

 solution to consist mainly of proteins with various organic and 

 inorganic substances. The constant presence of protein, fat, 

 carbohydrate, and inorganic salts, together with the existence of 

 protein-fat, protein-carbohydrate, and protein-inorganic salt 

 combinations, justifies the belief that not only such substances, 

 but also such combinations are absolutely essential to the exist- 

 ence of life." 



"The very important fact that the physical, nutritive, or toxic 

 properties of given substances may be greatly altered by a very 

 slight change in the arrangement of the atoms or groups of mole- 

 cules may be assumed to be conclusive evidence that a trifling modi- 

 fication in the chemical constitution of a vital substance may give 

 rise even to a profound alteration in its physiological properties." 



"This coupled with the fact that differences in centesimal com- 

 position have proved very inadequate to explain the differences in 

 the phenomena of living matter, implies that a much greater 

 degree of importance is to be attached to peculiarities of chemical 

 constitution than is usually recognized." 



"The possibility of an inconceivable number of constitutional 

 differences in any given protein are instanced in the fact that the 

 serum albumin molecule may, as has been estimated, have as 

 many as 1,000 million stereoisomers. If we assume that serum 

 globulin, myoalbumin, and other of the highest proteins may 

 have a similar number, and that the simpler proteins and the fats 

 and carbohydrates, and perhaps other complex organic substances, 

 may each have only a fraction of this number, it can readily be 

 conceived how, primarily by differences in chemical constitution 

 of vital substances and secondarily by differences in chemical 

 composition, there might be brought about all those differences 

 which serve to characterize genera, species, and individuals. 

 Furthermore, since the factors which give rise to constitutional 

 changes in one vital substance would probably operate at the 

 same time to cause related changes in certain others, the alterations 



