PHENOMENA FOLLOWING IMMUNIZATION 93 



the placenta which have chemical characteristics so well defined and 

 individual that the cytotoxic sera induced hy them have definite 

 organ specificity. The same to a more limited extent seems true 

 of kidney substance (Pearce). In most cases, however, in which 

 originally a specific cytotoxin was claimed, it has been possible to 

 show subsequently that the apparently selective injury was due not to 

 organ specificity alone but to the fact that the injection of tissue- 

 macerates, even when sufficiently freed from blood, induced the 

 formation of considerable amounts of hemagglutinins and hemol- 

 ysins. 



Pearce 58 expresses it as follows : "... it is evident that the 

 cells or the various organs of the body, while differing in morphology 

 and function, have certain (receptor) characteristics in common, 

 and that one type of cell may therefore produce antibodies affecting 

 several cells of differing morphology, but with like (receptor)^ 

 groups. This is shown by the sera prepared from washed liver, 

 kidney, pancreas, and adrenal, all of which may agglutinate and 

 hemolyze red blood cells and may cause degenerative changes also 

 in the liver and the kidneys. Some of these cytotoxic sera have no 

 effect upon organs for which they are supposed to have a morpho- 

 logical affinity, but exert a powerful lytic influence upon other cells. 

 Aside from nephrotoxin, which has a distinct injurious action upon 

 renal epithelium, the various cytotoxins studied (kidney, liver, pan- 

 creas, and adrenal) have no specific action in the morphological 

 sense." 



This opinion seems to be in harmony with that of most observers 

 who have studied the problem recently, at least as regards most of 

 the organ cytotoxins. Much of the promised light upon pathological 

 processes looked for when cytotoxins were first studied, has faded, 

 moreover, since it has been found that cytotoxins cannot be produced 

 by injection into an animal of cells, tissues, or fluids from its own 

 body. "Autocytotoxins" in general cannot be produced, a question 

 discussed at greater length in the chapter on lysis, in connection 

 with Ehrlich's work on the isolysins. 



The work outlined in the preceding paragraphs had thus ex- 

 tended the principles of antitoxin and lysin production beyond the 

 scope of pure bacteriology, and had shown them to possess the sig- 

 nificance of general biological laws. Similar generalization was soon 

 attained in the case of the agglutinins and in that of the precipitins. 

 In the former, the nature of the reaction limited it to observations 

 upon cells in suspension, and, in connection with the earlier experi- 

 ments upon hemolysis it was soon discovered that the erythrocytes 

 were often clumped before lysis could take place, when brought to- 

 gether with a hemolytic serum of moderate or feeble potency, or 

 when solution, for other reasons, was delayed. 



68 Pearce. Jour, of Med. Ees., N. S., Vol. 7, 1914, p. 13. 



