SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 375 



culate freely in Blood are amassed in the spleen, especially as they are 

 always small in number in the Blood when the spleen is enlarged. 



Thyroid Gland. 



1175. THE THYROID GLAND, Fig. 113, is a deep-red, 

 small, saddle-shaped gland, situated upon the windpipe 

 below the larynx, not usually conspicuous, yet can be felt. 



1176. THE THYROID GLAND is CONSTRUCTED of an 

 external sinewy tissue, the fibres of which intersect the 

 gland, forming small cavities lined with basement mem- 

 brane, the inner surface being clothed with ceils, and 

 the central cavity filled with a viscid, amber-colored 

 liquid containing granular matter. It is also construct- 

 ed of blood-vessels, lymphatics, and nerves. 



1177. THE USE OF THE THYROID GLAND can at pres- 

 ent only be said to be, to modify the Blood, of which 

 there is assurance, since its only inlet and outlet is blood- 

 tubes, and its structure is in part secretory. 



1178. Remark. THE THYROID FREQUENTLY ENLARGES to a very un- 

 comfortable size. This is more usual among females ; in certain families 

 also there is this tendency. But so far as the author has observed, in 

 this country, the enlargement of the thyroid is associated with the use 

 of hard water, especially that produced by magnesian limestone ; with 

 rare exceptions the enlargement can be prevented or diminished by the 

 use of soft water. The surest course for a person or family thus affect- 

 ed is to move to a locality where the water is soft and the air pure. 



Thymus Gland ; Suprarenal Capsules. 



1179. THE THYMUS GLAND is located back of the up- 

 per part of the sternum ; it is of noticeable size in infan- 

 cy, but diminishes to a trace at maturity ; use unknown. 



1180. THE SUPRARENAL CAPSULES are small bodies, 

 found at the summit of the kidneys ; use not understood. 



1181. THE THYMUS AND SUPRARENAL GLANDS ARE 

 CONSTRUCTED of sinewy and secretory tissue, and sup- 

 plied with blood-vessels, lymphatics, and nerves. 



1175. What is ? 1176. How is-? 1177. What is ? 1178. Does ? In what 

 Cases? 1179. Describe . 1180. Describe . 1181. How are ?. 



