1156 



RADIATION BIOLOGY 



sarcomas but do not render the renal epithelium neoplastic. The inci- 

 dence of induced tumors (Daels and Biltris, 1931) was low, many animals 

 dying too early of intercurrent disease. Biltris (1933) using the above 

 radium-string technique, in which the carcinogenic agents were /3 and y 

 radiations, induced in guinea pigs sarcomas of the meninges, metastasiz- 

 ing carcinomas of the gallbladder, and malignant tumors of the spleen 

 after a latency of eight to twenty-four months. In their last publication 

 Daels and Biltris (1937) described the induction of osteosarcoma in two 

 chickens by the collodion-string technique after a latency period of 



nearly five years. 



Following the work of Schurch and 

 Uehlinger (1931, 1947) (Fig. 18-3), numer- 

 ous articles appeared on the induction of 

 bone tumors in rabbits. These investiga- 

 tors implanted 1 mg of radium sulfate sub- 

 cutaneously in the jaw of a rabbit and left 

 it there for 20 days. The tumor appeared 

 one and one-half years afterward. Later 

 (1935) they placed vaseline impregnated 

 with 2-5 mg of mesothorium in the femora 

 of rabbits, inducing osteo- and poly- 

 morphous sarcomas. Sabin et al. (1932) 

 induced bone tumors in rabbits by intrave- 

 nous injection of radium chloride (approxi- 

 mately 5.1 mg) and mesothorium (approxi- 

 mately 7.7 mg) in eleven to nineteen 

 months. 



Ross (1936) implanted in the thoracic 

 wall of rabbits 0.1 mg of radium enclosed 

 in platinum tubes 1 cm long and with a wall thickness of 0.5 mm. 

 Earlier, the experimental induction of neoplasms had been successful 

 only when unscreened radioactive substance was used, with the exception 

 of some work of Schurch and Uehlinger, and the opinion was held that 

 a radiation was the principal carcinogenic factor. However, six of the 

 nine experimental animals of Ross developed a tumor adjacent to the 

 tubes ; one had an osteosarcoma, the others nonosseous neoplasms, indi- 

 cating that 7 radiation also induced tumors. These and earlier studies 

 are surveyed in Table 18-2. 



Petrov and Krotkina (1933, 1947), repeating the disputed work of 

 Lazarus-Barlow, implanted radium needles in the gallbladder of guinea 

 pigs and induced carcinomas of the biliary tract. The agent causing 

 spontaneous carcinoma of the gallbladder in man is not known; it is not 

 likely to be a radioactive substance. Therefore, such studies do not 

 contribute to the knowledge of spontaneous tumors or those likely to be 



Fig. 18-3. Osteogenic sarcoma 

 induced in a rabbit by injections 

 of thorotrast (after Schurch and 

 Uehlinger, 1935.) 



