MATERIALS AND METHODS

In a series of 94 female albino rats of the Sprague-Dawley strain, electrolytic lesions were placed in differentareas of the hypothalamus with the aid of the Horsley-Clarke instrument as adapted by Clark9 for use on the rat. Evipal was used for anesthesia (12 mg./100 g. bodyweight). The lesions were made with a unipolar electrode, by a direct current for 15 seconds, its intensity ranging from 0.8 to 2 milliamperes depending upon the size of the lesion desired. It should be noted here that after the milliammeter had been calibrated properly, the lesions produced with a current of 2 milliamperes. were invariably foundto be much larger than those reported by Brobeck, et al.,'and by Hetherington and Ranson"," withthe same current. For placing small, well-localized lesions, the hypothalamus was divided according too the Horsley-Clarke cobrdinates into discrete points whichwere separated from each other by 1 mm. in the rostro-caudal planes, and by% mm. in the lateral or parasagittal planes (See Figure 18 and Table 2, below). The area between the level of the para-