In the course of experiments to investigate the effects of certain salts and drugs on the cilia of the nasal mucosa it became apparent that changes in temperature affected the results. This was not unexpected. Cytologists have described with great accuracy the alterations in speed and effectiveness of ciliary action in mollusks and amphibians concomitant with thermal variations.1In fact, these activities could thus be accurately controlled. The reactions were reversible, within limits. By means of an apparatus constructed for the study of cilia in the sinus of the living rabbit and described elsewhere,2determinations for temperature were made on freshly removed human mucosa and checked against similar ones made on living rabbits. The results were recorded in cinematographs made at normal speeds. The portion of the apparatus immediately concerned in the experiments on temperature has not been previously described. It was used for extirpated membranes and consisted