Temperature Regulation in Albino Rats Correlated with Determinations of Myelin Density in the Hypothalamus.

Abstract

Monochromatic light and an electronic photometer were employed for the detn. of the densities of myelin stains retained by sections of the lateral hypothalami of litter-mate rats of progressively increasing ages. The photometric detns. were compared with the same type of detns. carried out on the pyramids of the medulla (an area completely free of nerve cells) and were correlated with the progressive improvements in the abilities of the respective animals to regulate their internal temps. when placed in a cold environment. It is concluded that myelination of the axons of hypothalamic cells may be one of the factors concerned with the attainment of temp.-regulating ability.