Abstract
The inhibitors to the three types of poliomyelitis virus contained in bovine serum were examined for age distribution, fluctuation in size by season, and hereditary relationship between mother and calf. A total of 61 dairy cows were used with her calves. The results obtained are summarized as follows.
1. The older became cows, the more frequently appeared the inhibitors, except that to type 3 of the virus, in their sera. It was impossible, however, to detect any inhibitor from sera of calves not more than six months of age.
2. Although no inhibitors were demonstrated in sera of newborn calves, considerable quantities of inhibitors were contained in sera of their mothers.
3. The inhibitors showed seasonal fluctuations in size.
