354 IMMUNOLOGICAL STUDIES 



ing, they were quickly destroyed. In tissue culture in chicken 

 plasma, rat sarcoma cells grew well in the presence of adult 

 chicken connective tissue, kidney, or liver. However, pieces of 

 adult chicken spleen caused practically total inhibition of growth 

 of the rat sarcoma cells. Chicken bone maiTOw caused a definite 

 retardation but not so marked an inhibition as that brought about 

 by spleen. When the combinations were made in vivo by implan- 

 tation on the outer membrane of the seven-day chick embryo the 

 results were similar, the grafted adult chicken spleen causing a 

 rapid regi"ession of the rat sarcoma tissue. Murphy also demon- 

 strated that pretreatment of adult rats with sublethal total body 

 x-irradiation rendered the animals tolerant to implantation of 

 mouse sarcoma. Recently Lindsley et al. ( 1955 ) have shown that a 

 functional implant of erythropoietic cells can be established in 

 x-irradiated rats by injection of homologous bone marrow carry- 

 ing an immunogenetic marker, and Makinodan (1956) has found 

 that when lethally irradiated mice are injected with rat bone mar- 

 row, being thus protected from the 30-day irradiation death, the 

 mouse red cells can be completely replaced by those of the rat. 



Effects of Antibodies on Development 



It is well known that antibodies produced against various kinds 

 of cells and tissues can have a destiaictive action on the homolo- 

 gous material. Reviews of such cytotoxic activity may be found 

 in various immunological texts (e.g., Raffel, 1953). Of more spe- 

 cial interest would be examples of antibody action that were not 

 necessarily lethal and led to specific alterations in development. 

 There have been reports of stimulating efi^ects of antisera, but 

 these have largely lacked substantiation. One of the most noted 

 of these is the reticulo-endothelial immune serum of Bogomolets 

 ( 1943 ) , which has been described as a veritable cure-all. While 

 cytotoxic or inhibiting in high concentration, the serum has been 

 claimed to be highly stimulating to cellular growth and activity 

 in low doses. Experiments by Pomerat (1945, 1946, 1949) and 

 others have failed to confirm the claims. A relative stimulation of 

 growth of homologous organs was reported by Weiss ( 1947 ) in 

 experiments in which antisera against cytolyzed adult liver or 



