Nov. 29, iQis Occurrence of Tumors in Domestic Fowl 403 



Attention has already been called to the fact that tumors occurred as 

 frequently in apparently normal birds which were killed as in those which 

 died from natural causes. From the data given in Table IV it may be 

 seen that many of the birds with tumors died from diseased conditions 

 apparently not related to the presence of the tumors. There were, 

 however, a number of cases where the size and distribution of the tumors 

 and the condition of the organs to which they were attached indicated 

 that the tumors were the probable cause of death. Associated with many 

 cases of tumors was a hypertrophied condition of the liver, spleen, or 

 kidneys. The liver was most often affected. In fact, 19, or 24.05 per 

 cent, of the individuals having tumors had enlarged and soft, friable livers. 

 In the absence of microscopic examination of these organs, it can not be 

 definitely stated that this hypertrophy was due to infiltration with tumor 

 cells. 



Table IV also shows that in several cases the immediate cause of death 

 was internal hemorrhage, either from the tumor surface, the tissue immedi- 

 ately beneath, or the hypertrophied liver or spleen. There were several 

 tumor cases in which death was recorded as due to internal hemorrhage 

 but in which the bleeding point was not recorded. It is probable that 

 in these cases also the bleeding took place either from the tumor or from 

 the hypertrophied liver or spleen. 



Our macroscopic examination of the tumors limited their classification 

 to the two groups of tissue tumors, formed of solid masses of tissue or 

 sometimes of large tissue masses inclosing masses of pus, mucus, or clotted 

 blood, and cystic tumors, which were sacs filled with liquid. Table IV 

 shows that 18, or 22.78 per cent, of the tumors observed were cystic, 

 while 59, or 74.68 per cent, were tissue tumors. There were two cases 

 (2.59 per cent) of ovarian tumors where cysts were attached to tissue 

 tumors. 



Table IV also shows the organ distribution of the tumors. It should be 

 borne in mind that this is essentially the distribution in females, as only 

 three males are included in the data. The organ most frequently affected 

 is the ovary (37.76 per cent ^ of all the tumors occur in that organ). The 

 oviduct wall and ligament harbored 18.36 per cent — that is, in the female 

 the genital organs are the organs most frequently affected by tumors. 

 The number and percentages for each of the other organs are given in the 

 table. Table IV also shows that in most cases the tumor was confined 

 to one organ. In 1 5 cases, however, the tumor had undergone metastasis, 

 since tumors of similar sorts occurred in 2 (11 cases), 3 (3 cases), or 4 

 (i case) organs. Attention has already been called to the frequent associ- 

 ation of hypertrophied livers, spleens, and kidneys with defined tumors 

 in other organs. 



' These percentages are calculated on the basis of 98 tumors, although they all occurred in 79 individuals 

 9842°— 15 4 



