EXPERIMENTAL EVIDENCE SUPPORTING THE CONCEPTION OF "ADAPTATION ENERGY"

Abstract

The expts. reported show that by giving gradually increasing doses of various alarming stimuli, one may raise the resistance of animals in such a manner that even treatment which would cause marked thymus involution in normals will have little or no effect on the thymus wt. Stimuli other than the one with which these animals had been pretreated will cause severe thymus involution which is usually even more pronounced than that obtained by the same dose of the same agent in the not pretreated animal. Using the response of the thymus as an index of resistance, it was shown that during adaptation to a certain stimulus, the resistance to other stimuli decreases. This conception receives further support by expts. showing that rats pretreated with a certain agent will resist such doses of this agent which would be fatal for not pretreated controls. Their resistance to toxic doses of agents other than the one to which they have been adapted decreases below the initial value. These findings are tentatively interpreted by the assumption that the resistance of the organism to various damaging stimuli is dependent on its adaptability. This adaptability is conceived to depend upon adaptation energy of which the organism possesses only a limited amount, so that if it is used for adaptation to a certain stimulus, the resistance to other stimuli will necessarily decrease. Adaptation to any stimulus is evidently always acquired at the cost of adaptation energy.