354 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



transplanted tissues. More marked than the injurious effect of the homoio- 

 toxins is that of heterogenous bodyfluids, containing heterotoxins, on trans- 

 planted tissues; these heterotoxins damage all transplanted tissues without 

 the cooperation of host cells. The action of sera on tumor cells has been 

 studied particularly by Lumsden and his coworkers. They distinguish: (1) 

 homoiotoxins which develop, for instance, in a rat after immunization with 

 Jensen rat sarcoma and rat spleen. They injure cancer and normal wandering 

 cells from the same species in tissue culture, but not other kinds of normal 

 tissue cells. These substances are heat-labile and are contained in the euglobu- 

 lin fraction of the serum; (2) normal heterotoxins which are injurious for 

 cells of all other species. They are very heat-labile and are also contained in 

 the euglobulin fraction ; they can be increased in quantity through immuniza- 

 tion; (3) immune heterotoxins which are directed specifically against the 

 species which has been used for immunization. These are stable, heat-resistant, 

 and are contained in the pseudoglobulin fraction; (4) and possibly in addition 

 to the species-specific antibodies, tissue- or organ-specific immune substances. 

 Lumsden believes that there is evidence as well that "anti-malignant" immune 

 substances develop in response to inoculation of cancer tissue into animals 

 of the same species in which the cancer originated, for instances, in response 

 to inoculation of the Jensen rat sarcoma into rats. These sera would act not 

 only on the kind of cancer which was used for immunization, but also on 

 various other types of cancer, irrespective of the species in which they 

 originated. However, other investigators (Phelps) find that such sera are 

 not specific for cancer cells, but contain heterotoxins which act equally well 

 on normal cells of the species to which the antigen belonged. Lumsden, 

 Macrea and Skipper themselves noted that such "anti-malignancy" sera kill 

 also young, not as yet much differentiated macrophages emerging from spleen 

 cultures; however, these sera do not affect the macrophages of the producer 

 of the antiserum. This is presumably due to the fact that in the latter case we 

 have to deal with autogenous cells, while the ordinary "anti-malignancy" 

 sera act either on homoiogenous or heterogenous cells. At present it appears 

 doubtful whether such anticancer sera exist. However, it is very probable 

 that heterogenous, and also homoiogenous cancer growth in an animal may 

 call forth the production of immune substances much more actively than do 

 normal adult tissues; but strange embryonal tissues likewise produce im- 

 munity, and it is very probable that the more active growth of cancerous 

 tissue as compared with inoculated adult normal tissue is at least one of the 

 factors that is responsible for the difference in the effectiveness of these 

 various tissues serving as antigens. 



By a different method Woglom attempted to prove the existence of im- 

 mune substances in the serum of rats inoculated with rat sarcoma 39, after 

 the spontaneous retrogression of these tumors. He absorbed the immune 

 substances which were present in the blood of these rats by means of a 

 mash of sarcoma 39. After subsequent extraction of the immune substances 

 from the sarcoma mash with Locke solution, this extract inhibited the growth 



