THE PINEAL 245 



Removal of the Pitituary. — It is now agreed that com- 

 plete removal of the pituitary is rapidly fatal, the terminal 

 event being ushered in with lethargy, general weakness, 

 tremors, cardiac weakness, subnormal temperature, and 

 coma. 



Removal of the pars nervosa alone causes no symptoms. 

 Removal of a large portion of the anterior lobe is incom- 

 patible with hfe, but when a small portion only is removed 

 there develops a condition resembhng dystrophia adiposo- 

 genitalis^ — atrophy of the genital organs and deposition 

 of fat. The same condition can be produced experi- 

 mentally when the pituitary is deprived of its blood 

 supply by section of the infundibular stalk. When this 

 is done the cells of the anterior lobe undergo atrophic 

 changes. 



The functions of the pituitary, so far as we know them, 

 may be thus summarised : — 



The anterior lobe is essential for hfe ; the posterior 

 lobe is not only not essential but its absence causes no 

 symptoms. 



The anterior lobe seems to have a profound influence 

 upon bodily, and particularly skeletal, growth. 



The biological significance of the physiological effect of 

 posterior lobe extract is not known. 



THE PINEAL GLAND 



This is a small body situated in the root of the third 

 ventricle. Morphologically it is related to the median eye 

 of the reptile. It is composed of epithehal cells with 

 profuse blood-sinuses. Proportionally larger in youth, it 

 afterwards undergoes atrophy. 



Little is known of its function. Abnormal growth and 

 sexual precocity have been variously associated with 

 excision, with disease, and with injection of pineal extract. 



