Chapter 20 

 Individuality Differentials and Tissue Culture 



In the living organism, tissues bearing strange individuality differ- 

 entials are injured by the homoio- or heterotoxins circulating in the 

 bodyfluids of the host, as well as by the cells of the host. The relative 

 importance of these two injurious factors differs in different species and 

 with different tissues. In higher organisms, the reactions against tissues 

 bearing homoiogenous individuality differentials are, as a rule, severe; 

 however, if tissues are grown in tissue culture, no special difference in the 

 effect of autogenous and homoiogenous serum or plasma serving as media 

 is noticeable. This follows from the observations of I. T. Genther and the 

 writer, which showed that the number of mitoses in the guinea pig thyroid 

 was about the same in vitro in autogenous and homoiogenous serum, when 

 it might be expected that quantitative differences in mitotic activity would 

 serve as a delicate indicator of the injurious influence of homoiotoxins. Like- 

 wise, the differences between the effects of homoiogenous and heterogenous 

 plasma or serum on tissue growing in vitro are much less than are the 

 corresponding differences between the effects of homoiogenous and heterog- 

 enous hosts on tissues transplanted into living animals. Thus Lambert and 

 Hanes noted that rat sarcoma cells may grow in guinea pig plasma for 30 

 days, in rabbit plasma for about 12 days, in dog plasma for 2-3 days, and in 

 pigeon plasma for 4-5 days, but no growth of rat or mouse tumor cells took 

 place in goat plasma. Also, motile cells of the spleen could grow out in 

 heterogenous plasma, and both rat sarcoma and rat spleen produced giant 

 cells in such a medium ; a culture of fibroblasts remained active, for a certain 

 time at least, in a heterogenous medium, but the injurious effect of hetero- 

 toxins became manifest more readily in normal fibroblasts than in certain 

 tumor cells (A. Fischer). There may be active in these cases, both the 

 strange organismal differentials, whose effect is graded in accordance with 

 phylogenetic relationship, and special toxic substances, whose action does 

 not correspond directly to this relationship. 



The same two factors play a role also in amphibian tissues growing in 

 vitro. Thus, Rhoda Erdmann cultivated skin of Bufo first in Bufo plasma 

 and Bufo spleen extract, next in Bufo plasma and frog spleen extract, and 

 in the end in frog plasma and frog spleen extract; by these means a gradual 

 adaptation of tissues to strange organismal differentials was achieved. The 

 skin of another amphibian species could likewise be cultivated in combina- 

 tions of heterogenous plasma and tissue extracts. Hitchcock found that frog 

 skin of a certain species grew equally well in autogenous and in homoiogenous 

 plasma or serum, and also in the bodyfluids of heterogenous species of 

 Rana. However, frog skin was rapidly killed in vitro by Necturus plasma 



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