436 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



taneously and in which periods of depression and of great intensity of growth 

 alternate; tumor cells which are in the phase of depression offer great diffi- 

 culty to transplantation. There were two facts known at that time which 

 demonstrated the dependence of the fate of the transplant on factors which 

 are present also in normal tissues, namely, the difference in the results of 

 auto- and homoiotransplantation of tumors, and the species-specificity of the 

 antigens in normal tissues which immunized a host against the growth of a 

 transplant, the latter indicating a parallelism between immune reactions against 

 tumors and against normal tissues and their proteins. Bash ford, Murray and 

 Cramer pointed out the species-specific factors in the production of immunity 

 against tumors and in the production of hemolysins and precipitins. Yet, they 

 considered the immunity against transplanted homoiogenous tumors as due 

 to a lack of the stroma reaction, a special phenomenon not heretofore de- 

 scribed in the transplantation of normal tissues. Moreover, as stated, they 

 did not attribute the specificity of the tumor tissue to its genetic constitution, 

 but to environmental factors which induce processes of adaptation in the 

 tumor to the organism in which it develops. These investigators conclude that 

 the "influence of individuality, i.e., the sum total of changes due to the past 

 life of the organism, will be to make any mouse different from all the others 

 and these differences will increase the longer the animal lives." In the new 

 host the environment is so strange that the cells cannot survive the interrup- 

 tion of their nutrition. Their failure to grow does not necessarily imply that 

 they would fail to proliferate in their new hosts if the conditions to which 

 they had been accustomed would be immediately supplied in the experiment. 

 "Cells which have lived and have become accustomed to the bodyfluids of one 

 mouse for, say, two years, may easily die or fail to adapt themselves when 

 transferred to the bodies of new animals." Autogenous tissues would then 

 differ from homoiogenous tissues in that the former have had a chance to 

 adapt themselves to the bodyfluids of the host, while homoiogenous tissues 

 have not had such an opportunity. It is evident that this conception differs 

 in some very essential respects from the conception of the organismal differen- 

 tials. The organismal differentials are the derivatives, the phenotypic mani- 

 festations of the genetic constitution of the fertilized germ cells and of the 

 tissues. The organismal differentials in host and transplant and their mutual 

 relationship represent the constitutional factors which determine transplanta- 

 bility of normal tissues and also of tumors ; other factors also enter into this 

 process. 



Bash ford, Haaland, Woglom, and more recently, Lumsden, attributed 

 therefore the transplantability of a tumor, in the main, to secondary processes 

 of adaptation which take place between the tumor and the host in which it 

 originated, or into which it had been transplanted. The origin as well as the 

 transplantability of tumors would therefore depend upon variable, fluctuating 

 factors. It is especially the older experiments of Haaland which suggested 

 this point of view. Haaland believed that he had shown the apparent influence 

 of environmental, and especially of nutritional, conditions on the character of 

 the animals and their ability to serve as hosts of transplanted tumors. But 



