20 Harry C. Schmeisser. 



2. In the Organs. (a) A diffuse and circumscribed, at times 

 nodular, infiltration of myeloid cells, in which the large mononuclear, 

 and mononuclear myelocyte with eosinophilic granules predominated, 

 although the other cells of the normal bone-marrow were at times 

 present. This myelosis involved especially the liver, spleen, kidneys and 

 bone-marrow, resulting in an extreme enlargement of the first three 

 organs. Almost all of the remaining organs showed infiltrations, but to 

 a less degree, (b) A change in the contents of the blood-vessels. The 

 proportion of white to red cells was greatly increased. The predomina- 

 ting cells were the same as those of the infiltration. 



CONCLUSION. 



In conclusion, if we consider that the cells, characteristic of both 

 leukaamic infiltrate and blood, were the same, and that under normal 

 conditions the mononuclear myelocyte with eosinophilic granules 

 occurs only in the bone-marrow and the large mononuclear only in the 

 marrow and blood, it is evident from the summarized facts, that the 

 above case must be considered a typical case of myeloid leukcemia. 



IV. EXPERIMENTAL LEUKEMIA. 



With material from the above case, the disease was successfully trans- 

 mitted into the fifth generation. A total of 105 animals were used in 

 conducting many different kinds of experiments. Of this number, 22 

 in all have developed leukaemia. In four additional animals, a definite 

 diagnosis could not be established, although the appearances were highly 

 suggestive. The strain has now been running for more than 13 months. 



This paper will be confined to a report of those series which deal with 

 simple transmission of the disease by the injection of an organic 

 emulsion. 



Five of these series were conducted, each consisting of 5, 10 or 15 

 fowls. The percentage of positives per series varied from 20-40 per 

 cent. Of the total number of 40 chickens injected, 13 became leukaemic, 

 i. e. 32.5 per cent. In addition, a definite diagnosis could not be made 

 in three, although the findings were very suggestive. 



PREPARATION OF MATERIAL, METHODS OF INJECTION, ETC. 



The material used for transmission was an emulsion of liver, and 

 sometimes of spleen also. It was prepared by thoroughly macerating 



