366 THE DUCTLESS GLANDS 



J. The Question as to a Functional Relationship between 

 the Pituitary and the Thyroid Bodies 



From the time when the ductless glands first began to be 

 known, there has been a decided tendency to regard them as 

 physiologically more or less related to one another. In the 

 earliest days, there can be little doubt that the grouping 

 together of these organs was very largely to be ascribed to our 

 uniform ignorance of their functions. But during recent years 

 a certain amount of information has been accumulated, which 

 renders it probable that there are true interrelationships 

 between certain of the glands endowed with the power of 

 internal secretion. The whole question constitutes a very 

 fascinating, albeit a very abstruse, chapter in the physiology 

 of internal secretion. We are, however, in this place concerned 

 only with a possible functional relationship between the thyroid 

 and pituitary bodies. 



Many of the suggestions which have been made were of an 

 a priori character. Cyon has put forward a theory of an 

 elaborate kind about the mutual function of the thyroid and 

 pituitary bodies, and he regards the latter as a centre from 

 which the vascular supply of the brain is influenced through the 

 former. 



Rogowitsch, in 1888, observed in rabbits, killed at periods of 

 from two to ten weeks after thyroidectomy, a marked hyper- 

 trophy of the pituitary body. This result was confirmed by 

 many observers. 



Quite recently Lydia M. Degener has found that the increase 

 in weight of the pituitary, after the thyroid glands have been 

 " completely removed " l from rabbits, runs parallel with the 

 time which intervenes between thyroidectomy and the death 

 of the animal. After an interval of 179 days, the pituitary body 

 had increased to about three times the normal size. 



In these hypertrophied pituitaries there is increased activity 

 of the cells of the pars intermedia, and in the proper nervous 

 part of the posterior lobe. In these situations, granular, 



1 Thin meaiiK, presumably, ihat the thyroid and internal parathyroid on 

 both sides were removed, leaving behind both external parathyroids. 



