392 WILLIAM H. COLE 



are concerned. He also found that the transplant metamor- 

 phosed in the manner typical of the region of the animal from 

 which it came, without regard to its orientation or to the location 

 of its new position. He concluded that in different regions of the 

 body the skin is self-differentiating, and that the development of 

 a certain color and pigment pattern in a region is not the result 

 of correlation between the whole animal and the skin. The 

 factors determining the typical color and pattern must therefore 

 be formed early in development, and are deposited in the skin. 

 This would explain why skin, transplanted to another region, will 

 develop its own typical markings regardless of the surrounding 

 skin. 



In a general discussion of transplantations, Barfurth ('14, 

 p. 579) says: 



Wahrend im Allgemeinen fiir Transplantationen tierischer und 

 pflanzlicher Objekte die Regel gilt, dass Unterlage und Transplantat 

 ihre Eigenart bewahren, sind aber doch Beeinflussungen der Komponen- 

 ten aufeinander bei der innigen Vereinigung moglich und unumgangHch. 



The striking experiments of Kornfeld ('14) on the transplanta- 

 tion of gills in Salamandra show that there must be a specific 

 substance for gills which causes the grafts to retain their typical 

 form and structure even after undergoing partial absorption and 

 reaching equilibrium. 



A very definite statement is made by Thomson ('17, p. 170) 

 to the effect that "there are as many protoplasms as there are 

 individuals, and in homoiotransplants the appearance of a foreign 

 protoplasm in the body calls forth ferments into the circulation 

 which destroy the transplant." 



The results which Uhlenhuth ('17) obtained by homoiotrans- 

 plantation of skin on Amblystoma larvae were like those of 

 Weigl's with Salamandra. Uhlenhuth found that ''individual 

 types of yellow spots of the skin of one individual remained 

 unchanged even when the skin was grafted to an individual whose 

 skin developed yellow spots of another type." He concluded 

 that the factor which is responsible for the kind of yellow spots 

 developed is contained in the skin itself and is specific. 



