TRANSMISSIBLE FOWL LEUKOSIS IS 



sarcoma was produced by intramuscular inoculation. Furthermore, by trans- 

 plantation, the sarcoma of this strain was carried through 28 animal passages 

 and then erythroblastic leukosis was produced by intravenous inoculation of 

 blood after the last animal passage. 



Uhl, Engelbreth-Holm and Rothe Meyer (206) reported on the production 

 and pathogenesis of the sarcomas associated with Strains Ti and R. The first 

 160 passages of Strain Ti and the first 126 passages of Strain R yielded only 

 erythroblastic leukosis. Subsequently subcutaneous and intramuscular inocula- 

 tions with material of these strains brought about local sarcoma development. 

 These workers were able to produce sarcoma by subcutaneous inoculation of 

 either washed leukotic blood cells or leukotic plasma although the incidence of 

 success was low. The sarcomas thus produced were slow and steady in growth 

 and of a "polymorphous fusocellular type" in which the type cell was a very 

 immature fibroblast. No differences of histological structure were noted between 

 the sarcomas produced by the two Strains, Ti and R. Sarcomas of Strain E-S 

 grew much more rapidly. Transplants of sarcomas of Strain Ti gave rise to 

 erythroblastic leukosis, sarcomas, and combinations of the two. The transplanted 

 sarcomas were feeble in growth and could not be successfully retransplanted. 

 The sarcomas of Strain R could not be transplanted. 



Strain 13 described by Stubbs and Furth (195) originated in a chicken in- 

 oculated with their Strain 1 of erythroblastic leukosis and in its subsequent 

 passages produced sarcoma (endothelioma) and erythroblastic leukosis. Kabat 

 (118) has studied a polysaccharide obtained from the mucinous material in two 

 tumors produced by Furth's Strain 13 agent. The chemical properties of this 

 polysaccharide are similar to those of a polysaccharide obtained from other mu- 

 cinous material, namely, the vitreous humor, umbilical cord, synovial fiuid, and 

 the mucoid hemolytic streptococcus. Stubbs and Furth (195) were unable to 

 arrive at any definite conclusions regarding the agent of this strain, but con- 

 sidered the following possibilities: (a) Strain 13 consisted of a single agent which 

 was capable of producing both sarcoma (endothelioma) and erythroblastic leukosis 

 and the agent was either of spontaneous occurrence in the first chicken to become 

 affected, or developed as a variant of Strain 1 agent, (b) Strain 13 consisted of two 

 agents each producing a characteristic reaction. They favored the belief that 

 Strain 13 was a single agent, although they found that implants of the tumor 

 tissue of Strain 13 would grow in chickens resistant to repeated inoculations of 

 pure leukosis agent. Furth (82) has found that he could readily separate his 

 Strain 1 agent from the Strain 11 agent (which causes fibrosarcoma only) when 

 the two have been inoculated into the same chicken. 



The transmissible strain of leukosis developed by Oberling, Guerin, and Boic 

 (151) had an obscure origin. A chicken unsuccessfully inoculated with the filtrate 

 of a Murray-Begg fowl endothelioma died with primary carcinoma of the liver 

 six months after inoculation. Two chickens were inoculated with material from 

 this bird and, six months later, one died with leukosis and a retrorenal myeloma. 

 The transmissible strain of leukosis was carried on from this individual. Of 104 

 chickens inoculated with blood or emulsions of the organs, 54 died with erythro- 

 blastic leukosis of which number 19 cases were associated with a granuloblastic 

 reaction and 11 cases developed a transient erythroblastic leukosis. Subsequent 

 passage of this agent with the use of blood or tissues kept in glycerin and inoculated 

 intramuscularly into experimental birds has in some instances provoked a neo- 

 plastic reaction in the connective tissues (144, 145). The neoplasms encountered 

 were fibroblastic, spindle-cell sarcomas, rich in collagen fibers ana sometimes 

 showing myxomatous changes. In two cases epithelial neoplasms developed at 



