638 THE INTERNAL SECRETIONS AND IMMUNITY. 



blood what we term "antitoxin." The evidence mainly con- 

 sists of the results of experiments in vitro, in which the affinity 

 of various tissues for toxins are shown. Thus, if to an emul- 

 sion of brain or -spinal cord in a salt solution there is added a 

 dose of tetanus toxin sufficient to kill ten rabbits, the toxin 

 will lose its power and prove harmless when injected into a 

 single animal. Evidently there must have existed in the tissues 

 thus used some substance capable of converting the toxin into 

 an inert body. 



Analysis of Ehrlich's theory, however, seems to us to show 

 several vulnerable points. In the first place, we are called upon 

 to conclude that the protoplasmic cells are so constituted as to 

 be prepared to meet each individual toxin in a special manner. 

 In other words, there must be as many side-chains or groups 

 of "toxophoric atoms" as there are toxins. If we survey the 

 field of pathology, the number of toxins so far isolated will 

 already appear quite large; if we add to these what toxins may 

 yet be discovered, we cannot but conclude that the cells of 

 which our tissues are built must indeed be complex bodies if 

 the hypothesis proves to represent facts. Again, a precon- 

 ceived antenatal arrangement of the molecular elements of the 

 cells with adjustment to the needs of existence in disease-ridden 

 communities becomes necessary. Hertwig's view that acquired 

 characters are transferable to the germ may serve to establish 

 a connection between the development of the lateral atom 

 groups and the numerous diseases to which the innumerable 

 generations have been exposed in the past. But, as previously 

 shown, experimental evidence, to which Ehrlich himself has 

 contributed the most convincing data, tends to prove the con- 

 trary: i.e., that immunity is not transferred to progeny through 

 the germinal cell. 



Again, Metchnikoff, Eoux, and other bacteriologists have 

 studied Ehrlich's hypothesis experimentally. Perhaps the most 

 striking of these is the repetition of Ehrlich's own and Wasser- 

 man's experiments, but followed by controlling experiments in 

 which carmine was used instead of brain and spinal-cord sub- 

 stance. Notwithstanding the substitution of this inert sub- 

 stance, however, the results were similar, the toxin being like- 

 wise rendered harmless by the carmine solution. It seems 



