FREQUENCY OF OCCURRENCE OF TUMORS IN THE 
DOMESTIC FOWL 1 
By Maynie R. Curtis, 
Assistant Biologist , Maine Agricultural Experiment Station 
The work of Rous, Murphy, Tytler, and Lange on the neoplasms of the 
domestic fowl has aroused some interest in the frequency of their occur¬ 
rence. In the course of io months Rous, Murphy, and Tytler 3 obtained 
without difficulty about 30 spontaneous tumors in living fowls. On 
examining 4,000 hens brought to a hotel, Ehrenreich 3 found 7 malignant 
tumors. All of these occurred in hens more than 1 year old, of which 
there were 1,000. 
For the last 8 years it has been the routine practice at the Maine Agri¬ 
cultural Experiment Station to make autopsies on all birds that either 
die from natural causes or are killed by accident or for data. In making 
these autopsies it has been the uniform practice to record the presence of 
tumors, the organs in which they occur, and whether or not the tumor is 
of cystic or solid tissue structure. No further study has been made of 
any tumor. The. data were collected primarily because of the possible 
effect of the presence of the tumor on the other data taken. In going 
over the records lately, however, their bearing on the frequency of the 
occurrence of neoplasms in fowls has seemed worthy of analysis and 
publication. The archives of the laboratory now contain 880 autopsy 
records sufficiently complete for use in this study. 
Of the 880 birds on which autopsies were performed carefully, 79, or 
8.98 per cent, had tumors of one sort or another. If we may consider 
these 880 birds a random sample of fowls as a whole, we may conclude 
that there are about 90 cases of tumors per 1,000 fowls. While these 
fowls are not a fair random sample, they are probably nearer one than 
any other equally large group on which data are at present available. It 
is possible, however, by the analysis of these records to study the fre¬ 
quency of occurrence of tumors in birds that die from natural causes com¬ 
pared to the frequency in normal birds that are killed. It is also possible 
to study the relation of the occurrence of tumors to age and sex. 
It is a well-known fact that in man there are many tumors which do 
not primarily affect the health of the host. This seems to be equally 
true of fowls. Table I shows the occurrence of tumors, first, in birds that 
1 Papers from the Biological Laboratory of the Maine Agricultural Experiment Station, No. 86. 
2 Rous, Peyton, Murphy, J. B., and Tytler, W. H. A filterable agent the cause of a second chicken- 
tumor, an osteochondrosarcoma. In Jour. Amer. Med. Assoc., v. 59, no. 20, p. 1793-1794.. 1912. 
3 Ehrenreich, M., and Michaelis, L* Ueber Tumoren hei Hiihnem. In Ztschr. Krebsforsch., Bd. 4, 
Heft 3, p. 586-591- 1906 . 
Ehrenreich, M. Weitere Mitteilungen fiber das Vorkommen maligner Tumoren bei Hiihnern. In Med. 
Klin., Jahrg. 3, No. 21, p. 614-615. 1907. 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
be 
(397) 
Vol. V., No. 9 
Nov. 29, 1915 
Maine—5 
