AbstractIn order to examine the glyceride content of whole mouse skin during the hair growth cycle, adult male C57Black mice (C57BL/6J) were plucked of hair in a region of the mid‐dorsum in order to initiate synchronous growth of new hair. Samples of whole skin were removed from each of three different mice on various days following plucking. Stages of the hair growth cycle were ascertained by examining microscopically a portion of each sample. The remaining piece of each sample, weighing approximately 225 mg, was minced, frozen with dry ice and weighed. Following this, each sample was ground in sand with a mortar and pestle and then extracted with ethanol‐ether, cleared by centrifugation and assayed for esterified fatty acids.This investigator found that during anagen the glyceride content of samples of whole mouse skin is nearly twice that found in telogen. It is possible that such cutaneous glycerides are major energy sources for the proliferation of hair, as well as for the development of the resting follile. On the other hand, the same factors which determine active hair proliferation may be responsible for glyceride accumulation under these conditions, and the two events otherwise could be unrela