Voit-Pettenkofer calorimeter, the animal occupant is theorized in relation to its environment, which is represented by the exchange of gas in the cage. Changes within the animal’s body are registered as changes in the composition of its external environment vis-a-vis gas. According to the logic of the calorimeter, knowledge about a particular body is inseparable from its surrounding conditions. In order to produce knowledge about the live, active body, scientists read into the body’s impact on the space it inhabited.
Atwater comments on the utility of dogs for research, writing, “In studying the laws of animal nutrition the most convenient organism, for many purposes, is that of the dog…In reading the accounts of the famous feeding trials conducted by Bischoff and Voit, one is surprised to see what control they obtained of the organisms of the dogs experimented with. By altering the kinds and quantities of food constituents, Voit was able to reduce both the flesh (protein) and the fat of the animal’s body or to increase both flesh and fat, or to reduce one or increase the other. Indeed, the manipulations effected in this way seemed almost equivalent to getting into the tissues and directly removing or adding flesh or fat at will” (Atwater 1895, 111-112).
