Occurrence of Tumors in Domestic Fowl 



399 



data on all the birds, whether or not their exact ages were known, into 

 two classes, young (under 2X years) and old (over 2j4 years). 



Table II. — Relation of age and sex to the occurrence of tumors in the domestic fowl 



Table III. — Summary of the data showing the relation of age and sex to the occurrence 

 of tumors in the domestic fowl 



This table shows that while only 7.46 per cent of the females under 

 2% years have tumors, 19.64 per cent of those over 2% years are affected. 

 The result for the males agrees essentially with that for the females, but 

 the number of males is too small to allow us to consider this result as 

 necessarily significant. It is, however, quite certain that the probability 

 of the presence of a tumor in a bird increases as the bird grows older. 



The records available for this study show in which organs the tumor 

 is located and whether it is of cystic or solid-tissue structure. These 

 data are given in Table IV. 



