210 



L n m 1) (• r I and 1 1 a n c s '^"0 and L a in I) c r t ^I'-'i) have 

 mainly sludicd llic cyloloxins of xarions niali«,manl (issue 

 ci'lls. Hats were ininiuni/.ed l)\ nionse sareonia. In Ihc 

 plasma of tin' innnunc rals. I)ils of mouse sarcoma were 

 cullivaled It was observed, llial (he sarcomatous tissue 

 from tile mouse remained (|uile inactive for a long time in 

 some 'Of the cultures and laler it was noted that a few 

 cells of iri'egular s]ia|)i' wandered out. In other cultures 

 the tissue disintegrated markedly. These experiments indi- 

 cated that the plasma from the immune rats was no longei* 

 a favorable medium for llu' cuilivalion af (he mouse sarcoma, 

 such as was the case when mouse sarcoma, was cultivated in 

 plasm.i from a non-immunized ral. Several experinu'nls of 

 the same kind gave similai' i-esulls. These experiments cor- 

 respond very well to what is known from experiments in 

 vivo. Mouse sarcoma inoculated into normal rats grows 

 actively for 8 — 10 days, producing a nodule which is after- 

 wards rapidly absorbed. In rats previously immunized, no 

 tumor nodules are formed. 



In other experiments guinea-pigs were immunized wilh 

 either defibrinated blood or ral sarcoma. It was then noted 

 that rat sarcoma cultivated in plasma from normal guinea- 

 pigs, gave uniform and good cultures. The rat sarcoma in 

 the plasma from the immune guinea-pigs, immunized wilh 

 rat sarcoma, showed no activity whatever. Also these expe- 

 riments showed that plasma from guinea-[)igs previously 

 treated with ral sarconui was unsuitable foi' the growth 

 of I'at sarcoma. The cytotoxins ])roduced by immunization 

 of gyinea-jiigs with rat sarcome is not specific, but is also 

 produced when guinea-pigs were immunized with defil)rin- 

 ated ral blood. 



Foot -i'^) has studied the cytotoxic action of the Ijone 

 marrow immune plasma on bone marrow cells in vitro. He 

 found that the bone marrow cells degenerated and died when 

 cullivate(' in the immune plasma from a rabbit, lie also 

 observed a precipitin reaction in the cultures. I-^ o o I clai- 



