402 PHYSIOLOGY. 



and inferior veins. The lymphatics terminate in the thoracic and 

 right lymphatic ducts. The nerve-supply to the thyroid body is 

 derived from the middle and inferior cervical ganglia of the sympa- 

 thetic and the pneumogastric. Their nonmedullated fibers adhere 

 very closely to the vessels. 



Function. ^It was shown by one observer that gentle pressure 

 upon the lobes of the gland caused the contents of the gland-acini, 

 or vesicles, to flow into the peripheral lymphatics. This was later 



a. 



v. 



Fig. 145. Parathyroid of Dog (Morat and Doyon). (VIALLETON.) 



c, Capsule, c.c, Partition of connective tissue in the thickness of the organ. 

 c.p, Epithelial cell of the parathyroid, v, Capillary. 



confirmed by the work of microscopists, and the colloid nature of the 

 secretion was also recognized. The vesicular epithelium is a true 

 secretory gland-tissue which separates the colloid material from the 

 blood. The secretory character of the epithelium has been further 

 shown by the injection of pilocarpine. Following its administration 

 there results a remarkable increase in secretion of the colloid sub- 

 stance. It has been demonstrated that the expressed juice of a thy- 

 roid gland of a dog produced coma in another animal three hours 

 after its administration. 



