ANIMAL EXPERIMENTATION AND PROTEAL THERAPY 283 



of immunization. As a case in point, note the comment of a very 

 industrious and laborious compiler, reviewing the literature of the 

 subject, when referring to the experiments of De Fano, above 

 noted, as follows : 



"As lymphocytes appeared in great numbers about inoculations 

 of immunizing material during the evolution of resistance, their 

 relation to this condition could not be denied. ... In growing 

 carcinomata they were to be found only in places where local 

 healing was in progress. A carcinoma cell seemed to exert some 

 sort of specific influence on the lymphocyte, and the latter to 

 spread the resistant state throughout the organism." 



In the light of the interpretation of the action of the lympho- 

 cytes that furnishes the chief thesis of the present monograph, 

 which will be elaborated presently, such a phrasing seems not less 

 ridiculous than the suggestion that the horse is pushed before the 

 carriage. 



To say that lymphocytes "were found only in places where 

 local healing was in progress" is a little as if one were to note 

 the curious coincidence that, in a certain house, rats were to be 

 found only in places where cheese was disappearing. 



Scarcely less absurd seems the interpretation that has been put 

 upon the widely heralded experiments of Ehrlich, as repeated by 

 others, in what has come to be known as the zigzag transplanta- 

 tion of tumors. It will be recalled that in this experiment a tumor 

 from a mouse is transplanted to the body of a rat, where it grows 

 for a time, and then begins to undergo regression. Before it has 

 entirely regressed, it is taken from the body of the rat and trans- 

 ferred to the original host, where it again takes on more or less 

 energetic growth. It will be recalled that Ehrlich explained this 

 with an elaborate theory of so-called atrepsia, according to which 

 there are certain chemical constituents in the organism of the 

 mouse that are essential to the growth of the mouse tumor; that 

 a certain quantity of this material is transferred with the tumor 

 to the body of the rat, and that when this transferred portion is 

 exhausted, the growth can no longer continue in the body of the 

 rat. 



In the light of the present thesis, the explanation of zigzag 

 transplantation would be simply that the transplanted tumor grew 

 for a short time in the body of the rat because a certain time was 

 required to muster the companies of corpuscles to combat the law- 

 less cells. When the corpuscular defenders had been aggregated 

 in sufficient numbers, the fight with the cancer cells would turn 

 in favor of the host, and the cancer would begin to regress. Now, 

 however, the remainder of the cancer cells are retransferred to the 

 mouse, where, as a matter of course, they continue to grow be- 

 cause it had already been demonstrated that the body of that par- 

 ticular mouse was not competent to produce corpuscles and their 



