316 



Diseases of Poultry 



to determine the point of origin. Certain lymphomata are 

 more or less alveolar in' structure ; others grow diffusely 

 through the tissues. The tumor may be confined to the 

 fixed tissues so that it is essentially extravascular, or the 

 tumor cells may also occur in the circulatory blood constitut- 

 ing a lymphatic leukemia." 



Probably the second most frequent type of connective 



Fig. 68. — Sarcoma Chicken Tumor No. I, Second Generation. (After 



Rous.) 



tissue tumor is sarcoma. This may occur as simple sarcoma 

 or it may occur in combination with one or more of the other 

 types. That is, it is a generalized and simple tissue which 

 may represent the complete adult stage of a tumor, as Rous 

 Chicken Tumor No. I, and Chicken Tumor No. XVIII. 

 However, since it is a simple generalized tissue, it may also 

 represent an early stage in the development of one of the 

 other forms of connective tissue tumors. In these cases it 

 remains as a matrix in which the further developed tissues 



