256 



UNCONSCIOUS NERVOUS OPERATIONS 



Svpraren a I 



Cortex 



-Medulla 



Pyramids 



new thyroid tissue to the food, or even by subcutaneous 

 injection of the juice of a healthy gland. It is concluded 

 that the gland either forms, or helps to form, some sub- 

 stance needful to health, or has some place in the destruc- 

 tion of deleterious substances in the system, but positive 

 knowledge in respect to it is lacking. 



369. The Thymus Gland lies in the thorax beneath the 

 sternum (Fig. 117). It is a small organ, weighing only 



about half an ounce at birth. 



< .1111 



After growing with the body 

 until the second year it gradu- 

 ally shrinks away, and before 

 the age of sixteen usually 

 disappears. Its use is quite 

 unknown. The thymus of 

 calves and lambs forms an 

 article of food called sweet- 

 bread. 



370. The Suprarenal Capsules 

 (Fig. 118) are small organs 

 Fig. 11 8. -^Longitudinal section of resting on the upper portion 

 kidney. of the kidneys. They are 



supplied with an abundance of blood vessels and nerve 

 fibers and nerve cells. It has been found that their 

 removal from animals is invariably and quickly fatal. 

 All that can yet be said as to the function of these bodies 

 is that they appear to form something which is essential 

 to the healthy tone of the muscles. 



Ureter 



