THE INFLUENCE OF HUMIDITY ON THE BODY TEM-. PERATURE OF CERTAIN POIKILOTHERMS

Poikilothermic animals are commonly accredited with possession of a body temperature closely approximating that of their environment. In general this appears to be true. However, there are some eases where the body temperature of certain “¿coldblooded†• animals may be very unlike that of their surroundings. Such examples are given by Rogers and Lewis (1916) in a table which they have compiled from the investigations of numerous workers. It shows that not all investigators agree even as to the temperature of the same species. It is probable that much of the discrepancy is due to different types of method. On the other hand, a more careful examination of the conflicting results of various authors as to the correspondence between body and environ mental temperature shows that the greatest variations occur when ani mals are subjected to atmospheric conditions. The factors which influence the temperature of animals may be classified as follows: intrinsic—those that lie within the organism and act to produce a temperature different from that of the environment; extrinsic—those imposed on the animal from without. The extrinsic factors are (1) conduction and convection, (2) radiation, (3) evapora tion of water. A discussion of the role played by each factor is given by Pearse and Hall (1928). It is the purpose of this paper to study the influence of the third factor, namely, the evaporation of water, on the body temperature of various poikilotherms. EXPERIMENTAL METHOD