other feathers (Greenwood and Blyth,' Parkes and Selye"). These changes, taken in connection with the effects of hyperthyroidism reported here, suggest a relative increase in extent of the ventral field of saddle feathers grown under conditions of hypothyroidism. The appearance in the breast tracts of longer, saddle-like feathers with restricted barbulation following thyroidectomy is in all probability likewise associated (among other germinal changes) with a ventral field of greater or lesser extent. It should be a matter of considerable interest to alter experimentally the balance of other hormones in thyroidectomized birds in order to test the specificity of thyroxin in determining and maintaining the limited ventral triangle of feather germs of different tracts.
PThe need for a method capable of evaluating germicides for chemotherapeutic use is universally recognized. Obviously, the first requirement is that the method should simulate as nearly as possible the conditions met in the animal body. In addition it should be relatively simple and should yield information regarding the action of the test substance on bacteria, and on animal tissues, in terms which would permit a direct comparison of the respective effects. The method of Lambert,' employed more recently by Salle,2 does not seem to fulfill these requirements, since the parasitotropic and organotropic properties of the disinfectant are tested under profoundly different conditions. Moreover, it is based on a tissue-culture technic which is time consuming and laborious.The manometric method proposed here has proved simple, rapid, and remarkably flexible. It permits the conditions of testing to be modified at will, and at the same time allows wide latitude in the 5Greenwood,