Frogs (Rana temporaria) were narcotized for 15 min. with a 1.3% soln. of ether, then killed and fixed. Histological investigation showed that the nuclei of the anterior horn cells of the spinal cord had lost 29.2% of their vol. (207 [mu]3 as against 293 [mu]3 in the controls). If the animals were killed 24 hrs. after the narcosis, the avg. vol. of these nuclei was found to be increased to 327 [mu]3. Similar observations were made on the nuclei of the basal cells of the epidermis, though the vol. found in non-narcotized control animals had not yet been reached 24 hrs. after ether narcosis. Similar narcosis expts. with 5% ethyl alcohol gave the following results Immediately after narcosis the avg. nuclear vol. of the anterior horn cells fell from 205 [mu]3 to 127 [mu]3; a post-narcotic nuclear enlargement to 193 [mu]3 appeared 2 hrs. later, following which there occurred a reduction to 162 [mu]3 after 24 hrs. In the basal cells of the epidermis similar results were obtained. Nuclear enlargement due to stimuli, as well as reduction of the nuclei following loss of water due to narcotics, may permit conclusions regarding the activity of the nuclei.