286 



BIOLOGY OF THE LABORATORY MOUSE 



F'nvdl confirmation, however, came from two series of experiments, one b\- 

 Strong (77, 78) and a still more importance piece of work by Bittner (9). 



Strong's 1926 (77) paper established a "one gene" ratio in the case of a 

 transplanted adenocarcinoma dBrCsp. This climaxed the long series of 

 tested tumors which had begun ten years earlier. 



His later paper (78) described an interesting tumor FiDb which showed a 

 four gene ratio in F... One of the genes which alTected the growth of the 

 tumor was, however, sex-linked. It thus provided important confirmatory 

 evidence of the Mendelian nature of the susceptibility to tumor transplants. 



Bittner's work was with certain transplantable tumors which occurred 

 spontaneously in Fi hybrid mice. It was, in some ways, related to an earlier 

 piece of work reported by Little and Johnson (49) . 



In this earlier experiment splenic tissue had been used instead of tumors. 

 Three groups of mice were used. These were (a) Japanese waltzers, (b) 

 Bagg albinos and (c) Fi hybrids between these two strains. Bits of spleen 

 from animals in each group were inoculated subcutaneously into animals of 

 the same group and into mice from the other two groups. In Table 7 are 

 shown the results obtained in animals where the physical condition remained 

 good throughout the experiment. 



Table 7 



The Results of Transplanting Spleen Tissue w^ithin and between Two 



Inbred Strains of Mice and Their Hybrids 



The Fi spleens failed to grow in the Japanese waltzers, thus showing that 

 they were characteristic of hybrid animals. On the other hand they grew in 

 other Fi hybrids as did the Japanese waltzers' spleens. 



The tumors with which Bittner worked originated in Fi hybrids between 

 the dilute brown (dba or *'D ") strain and an albino (A) strain derived from 

 Bagg albinos (Fig. 130). 



