TRANSMISSIBLE FOWL LEUKOSIS 35 



weekly injections of benzpyrene was reported by Jarmai and Balo (104). A series 

 of 16 passages of the transmissible agent from one of these cases was made and 

 the agent was found to remain active in glycerin solution. These results were not 

 reproducible and Jarmai and Balo, therefore, were inclined to believe that the two 

 instances of disease in the treated chickens were spontaneous. Methylchol- 

 anthrene was found by them to give negative results when injected in the chicken. 

 They also administered a 0.25 percent solution of maretin (an antipyretic drug 

 which has been known to produce an anemia and leukocytosis) in 0.1 cc. doses 

 at weekly intervals. An increase of erythrocytes and leukocytes began about 

 the eighth to tenth day after injection of maretin. The majority of the leukocytes 

 were myeloblasts and poikilonuclear cells (leukoblasts). After a second injection 

 an anemia began to develop although the leukocytes continued to increase. The 

 chickens lived from two to three months during which time they became emaciated 

 and more anemic. The organs showed only a very mild reaction, not like typical 

 leukosis. Attempts were made to transmit the disease from two of the chickens 

 which had received the maretin solution with the result that the condition was 

 carried through two passages in each instance, but could be carried no further. 



Yudina (219) observed leukemoid reactions in chickens injected subcutaneously 

 with a Yi percent solution of 1:2:5:6 dibenzanthracene in chicken fat. These 

 injections were administered in 0.1 to 0.2 cc. doses every six days for five months, 

 and the birds were observed for a total of eight months. Among 42 chickens thus 

 treated she observed one case of "leucaemia" (granuloblastic leukosis?), three 

 cases of "aleucaeniic myelosis" (myelocytoma?) one of which was associated with 

 development of sarcoma at the site of injection, three ca.=;es of "erythroblastosis" 

 (erythroblastic leukosis?), and one case of local sarcoma development without 

 leukosis. Unfortunately, there is no mention of attempts made to transmit the 

 experimentally produced conditions. 



Thomsen, Engelbreth-Holm, and Rothe Meyer (201) report an unusual cir- 

 cumstance in which erythroblastic leukosis occurred in a number of chickens 

 which received whole blood mixtures from other birds not affected with leukosis. 

 They were unable to give an explanation of this development which happened 

 in the course of certain unrelated immunological studies. 



Winternitz and Schmeisser (216) observed the occurrence of leukosis in the 

 course of some experimental work with Salmonella gallinarum. They suggested 

 the possibility of reproducing leukosis by properly regulated doses of the fowl 

 typhoid bacillus. 



Emmel (46) in an extensive series of publications (for references see his paper 

 cited) has discussed the results of his work indicating that fowl leukosis among 

 other diseases can be produced by the action of members of the Salmonella genus 

 of bacteria. Recently he has expressed the belief that atmospheric conditions, 

 such as decrease of oxygen and increase of carbon dioxide, may be a factor con- 

 tributing to the induction of leukosis. The fact that Olson and Goetchius (158) 

 and Beach and Twisselmann (10) were unable to confirm Emmel's findings (the 

 production of these diseases by members of the Salmonella genus) tends to in- 

 validate this portion of his work. The condition of hemocytoblastosis so fre- 

 quently mentioned by Emmel in his publications is difificult to visualize and com- 

 prehend from his descriptions. Recently, Blount (16) has reviewed the subject 

 of so-called hemocytoblastosis of the chicken and suggests that the term has 

 been used by Emmel in a broad sense to indicate a number of alterations, some 

 physiological and others of minor pathological significance, which represent a 

 type of myeloid response and are not in themselves to be considered as a specific 

 disease. 



