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STUDIES IN ADVANCED PHYSIOLOGY. 



position, possibly, to treat them in connection with the di- 

 gestive tract. This is at least allowable, since the func- 

 tion of several of these structures is practically not at all 

 understood, and so could not be scientifically treated any 

 better in connection with other topics. These ductless 

 glands include the thyroid glands, the thymus gland, the 

 spleen, the adrenal bodies, scattered lymphatic glands, the 

 carotid glands, and the coccygeal gland. 



1. The thyroid glands. The thyroid glands are two 

 large dark reddish, vascular structures situated in the neck 

 just below and to the side of the voice-box. The two lobes 

 are usually connected with a transverse portion called the 

 isthmus. It varies in length, each lobe measuring an inch 

 to an inch and a half, while the thickest portion is about 

 an inch. The isthmus connecting these two lobes is about 

 one-half an inch wide and about three-quarters of an inch 

 long. Examined roughly the structure of the organ seems 

 to be granular. This is borne out by a microscopic examin- 



Fig. 120. SHOWING THE RELATIVE POSITIONS AND SIZES OF THE THYMUS AND THYROID 



GLANDS IN A CHILD. (After Sappey.) 



1,2,3,4, thymus gland; 6, thyroid gland, covered with a number of blood-vessels. 

 All the other numbers refer to blood-vessels. 



ation of the gland, which shows that it is composed of in- 

 numerable vesicles which are bound together more or less 

 firmly by intervening areolar tissue. Each vesicle is usu- 

 ally quite small, at best just visible to the unaided eye. 



