GROWTH AND CHEMICAL PURITY 273 



power as a result of whose action metabolism is 

 produced. 



Pregnancy and Eclampsia 



Although, through the action of the kinetic system, 

 the species preserves a relative purity of its chemical 

 composition, observation shows that this standard is 

 not always identical. The development of serologic 

 knowledge has disclosed certain variations among 

 normal individuals. Hektoen showed that the serum of 

 particular groups of individuals contained isoglutinins 

 for certain other groups, and no isoglutinins for still 

 other groups. The source of this difference has not 

 yet been determined. Not only is the lack of absolute 

 chemical homogeneity among individuals shown by 

 serologic tests, but it is also shown by the more rigid 

 test of the transference of living parts of one animal 

 or man to another. These observations have been 

 made on a large scale in the direct transfusion of blood, 

 in skin grafting and in the transplantation of organs. 



In blood transfusion hemolysis of the transferred 

 blood might be easily understood when the recipient 

 is abnormal, as, for instance, where there is pernicious 

 anemia; but there is. also a slight hemolysis of trans- 

 ferred blood in some apparently normal individuals. 

 This would indicate a difference in the chemical nature 

 of normal individuals. As to skin grafting, I have 

 observed that, in cancer, skin grafts from the patient 

 himself are far more successful than skin grafts from 

 another individual. Even in the absence of disease, 

 skin grafts from another part of the same individual 

 grow better than grafts from another individual. Carrel 



