Nov. 29 ,1915 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 1 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 15 cases, however, the tumor had undergone metastasis, 
since tumors of similar sorts occurred in 2 (11 cases), 3 (3 cases), or 4 
(1 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 
