370 THE DUCTLESS GLANDS 



of Gentes that this structure has a function similar to that of 

 a choroid plexus. 



The Elasmobranch pituitary, as we have already seen, is 

 quite different in structure from the pituitary bodies of mam- 

 mals, birds, and Teleosts. There is no differentiation into 

 anterior and posterior lobes. According to Herring, there are 

 no cells precisely corresponding to those of either the anterior 

 portion or the pars intermedia of the mammalian body. The 

 presence of the true nervous portion seems also doubtful. 

 Extracts of the Elasmobranch pituitary give rise to no 

 characteristic physiological effects. 



N. Diseases of the Pituitary Body 



1. Introductory 



According to Gushing, a pronounced constitutional dys- 

 pituitarism is not incompatible with a tolerable state of health 

 and comfort. In regard to symptoms due to each of the two 

 lobes, there may be an overaction or underaction of one lobe 

 only, or an overaction of one lobe associated with insufficiency 

 of the other. In the minds of many authorities the subject is 

 rendered still more complex by a tendency to regard every 

 disorder of the ductless glands as a poly glandular disease. 

 This is said to be sometimes so pronounced as to make it 

 doubtful which of the organs is primarily at fault. It is 

 generally believed that derangement of any one of these corre- 

 lated glands leads to disturbances in others, but a primary 

 disorder of any one will produce its own special symptoms. 



A functional hyperplasia of the pars anterior promotes 

 tissue growth, chiefly shown in the skeleton, skin, and sub- 

 cutaneous tissues, and at the same time there is an excitatory 

 effect on the reproductive organs, as seen in the secondary 

 sexual characters. On the other hand,, insufficiency of the 

 anterior lobe inhibits skeletal growth and sexual development. 



Little is known about functional hyperplasia of the posterior 

 lobe. This part seems to be concerned with tissue metabolism. 

 Insufficiency gives rise to slowed metabolic processes. There 

 is a high tolerance for carbohydrates, which are stored as fat, 

 there is drowsiness, slow pulse and respiration, subnormal tem- 

 perature, low blood-pressure, etc. This complex of symptoms 

 just described strikingly resembles the phenomenon of hiberna- 



