INTERRELATION OF THE ENDOCRIN ORGANS 921 



uterine death of the fetuses; 21 offspring, however, were secured. The 

 weight of their suprarenals averaged 53 per cent less than that of normal 

 animals of the same age. This depression was tentatively ascribed to 

 flooding of the fetal circulation with an excess of suprarenal products 

 due to stimulation of the suprarenal glands of the mothers. The inter- 

 pretation is, of course, open to question. 



The effect of experimental thyroid deficiency has also been studied 

 by a number of investigators. Hofmeister, in 1894, performed thyroid- 

 ectomy upon many young rabbits and studied the results in various organs. 

 No significant difference between the suprarenals of the experimental and 

 normal animals was established. Definitely negative results were also 

 obtained by Bensen (1902). Most investigators, however, who have 

 studied the results of thyroidectomy have devoted little attention to the 

 suprarenals. Gley and Quinquaud (1914) reported marked increase in 

 the relative weight of the suprarenals of rabbits after thyroparathyroid- 

 ectomy. This increase was interpreted, however, as indicating not hyper- 

 function but degeneration. Tatum (1913) removed the thyroid from 

 young rabbits 2 to 3 weeks old, leaving the inferior parathyroids intact. 

 The operation resulted in hyper pi a si a of the suprarenal medulla and aug- 

 mentation of the lipoid material in the cortex. Carlson has stated that 

 "After complete thyroidectomy we invariably get a hypertrophy of the 

 suprarenals to two or three times their normal size." Herring (b) (1916), 

 on the other hand, in the case of 5 thyroidectomized rabbits, failed to 

 obtain any significant effect upon either the weight or the epinephrin con- 

 tent of the suprarenals. Stewart and Rogoff (1921) have reported that 

 the average weight of the suprarenals of 25 thyroparathyroidectomized 

 rabbits was considerably greater than normal, and that the enlarged glands 

 contained proportionately as much epinephrin per unit weight as those 

 of normal animals. Eor a more detailed discussion of the evidence along 

 these lines Herring's paper of 1920 may be consulted. 



So far as the writer is aware, the study of clinical cases of thyroid 

 disorders has not contributed any significant data on the thyroid-supra- 

 renal relationship. 



In view of the fact that the suprarenals are known to hypertrophy 

 from a variety of causes, such as pregnancy, prolonged muscular exercise, 

 avitaminosis, and perhaps intoxication of various sorts, the interpretation 

 of the foregoing data is difficult. The weight of the evidence, although by 

 no means conclusive, seems to indicate that the thyroid stimulates the 

 suprarenals. The problem is worthy of further investigation, using a 

 variety of spiecies of animals. 



Relation between Thyroid and Hypophysis, The existence of a 

 relationship between the thyroid and the hypophysis is perhaps the most 

 satisfactorily demonstrated of all the endocrin interrelationships. The 

 experimental evidence is somewhat extensive and is fairly well supported 



