102 ANTIGENS AND ANTIBODIES 



apparent, and while such cells, hence represent excellent test objects 

 for the purpose of studying the nature and mode of action of the 

 immune sera in question, the demonstration of a neurotoxic, hepato- 

 toxic, or nephrotoxic influence is a more difficult task. Delezenne, 

 it is true, claims to have obtained hepatotoxic sera by injecting suit- 

 able animals with dog's liver, and states that such sera will produce 

 specific impairment of the liver function in dogs, as evidenced by 

 diminished elimination of urea, by increased excretion of ammonia, 

 and the appearance of leucin and tyrosin in the urine, and that 

 digestive glucosuria may also develop when the animal receives an 

 abundant supply of sugar; in some instances death even occurred. 

 The same writer further claims to have obtained a neurotoxic serum 

 which would produce vacuole formation and chromatolysis in gan- 

 glionic cells. Lindemann and Nefedieff further announced that 

 with a nephrotoxic serum they could bring about the development 

 of albuminuria, uremia, and death, and that postmortem there was 

 widespread degeneration of the epithelial cellsof the convoluted tubules. 



Isocytolysins. Observations such as these naturally raised the 

 question whether cytotoxin production only occurs when cells from 

 a given animal are injected into an animal of an alien species, i. e., 

 whether heterocytotoxin (sive heterolysiri) formation only is possible, 

 or whether something analogous does not occur when cells from one 

 animal are injected into another one of the same species. Ehrlich 

 and Morgenroth could show that the production of such isocytotoxins 

 (sive isolysins) can actually occur, for on injecting goats with goat 

 blood he found that the serum of the injected animals had become 

 hemolytic for goat corpuscles. Metschnikoff similarly found that 

 an isospermatoxin is formed when a guinea-pig is injected with 

 spermatozoa from another guinea-pig, as is evidenced by the fact 

 that such a serum will rapidly immobilize the spermatozoa. This 

 was first shown in vitro, but subsequently also established for the 

 living animal, for on injecting male mice with a corresponding 

 serum they were rendered sterile and coincidently the remarkable 

 observation was made that the semen of such animals had lost its 

 antigenetic properties, viz., that upon injection into other animals 

 it had lost the power of calling forth a corresponding formation of 

 spermatotoxin. 



Auto-antibodies. Further observation along these lines then led 

 to the important discovery that iso-antibody formation not only 



