STUDIES ON THE CONDITIONS OF ACTIVITY IN ENDOCRINE GLANDS

When insulin in an amount which reduces blood sugar below the common physiological percentage is administered to persons suffering from diabetes, characteristic symptoms occur which have been called “hypeglycemic reactions. ” They include pallor, rapid pulse, dilatation of the pupils and profuse sweating (1). These are indications of activity of tJhe svmpathetic division of the autonomic system and, as is often the case when that system is excited, there are tremors in skeletal muscle. Similar signsdilatation of the pupils, erection of the hair, salivationhave been reported as occurring in cats after insulin injections (2), and these too are explicable as results of svmpathetic nervous discharge. A natural inference from this evidence that the reduction of blood sugar by insulin involves sympathetic impulses is that adrenal secretion, known to be subject to such impulses, might be increased. Stewart and Rogoff have reported that in three cats, in which the influence of insulin on adrenal secretion was investigated, “no definite effect of any moment could be made out” (3). Since their method, however, gives negative results in their hands and positive results in ot#her hands (4), their failure should not be regarded as significant.3