[Growth and heat resistance of rats repeatedly exposed to heat during early ontogenesis].

The influence of a 10-fold heat training from the 1st to the 10th to the 20th, and from the 20th to the 30th days after birth on further growth and resistance of the animals to the high temperature was investigated. The growth and survival of rats was found to depend on the regimen of heat training. The animals aged 10 to 20 days proved to be most sensitive to the action of high temperature. Heat resistance of these rats turned out to be maximally increased at the period of primary sexual maturation, and the growth rate was retarded in comparison with the animals subjected to heat training at other age periods.