THE DUCTLESS GLANDS 



1191 



lobe. One must therefore conclude that the colloid material secreted by 

 the cells of this part passes directly into the third ventricle. The amount of 

 colloid material increases in animals which have undergone extirpation of 

 the thyroid gland. 



Our first clue to the importance of this organ in the normal processes 

 of the body was furnished by the observations of Pierre Marie, who found that 

 the morbid condition of ' acromegaly ' is associated with tumours of the 



FIG. 549. Mesial sagittal section through the pituitary body of an adult monkey 

 (semi-diagrammatic). (After HERRING.) 



a, optic chiasma ; b, third ventricle ; c, tongue-like process of pare intermedia ; 

 d, epithelial investment of posterior lobe ; r, anterior lobe ; /, epithelial cleft ; 

 g, pars intermedia ; h, posterior lobe. 



pituitary gland. This disease consists in an increased growth of certain 

 parts of the skeleton, especially the lower jaw and the extremities of the 

 limbs. Headache is often present, and there may be polyuria and affection 

 of the eyesight. When this disease occurs during the period of active growth 

 there may be an increase in length both of the limb-bones and of the trunk, 

 and most of the giants, which are shown from time to time, are examples of 

 this pathological condition of ' gigantism.' It seems probable that this 

 condition is due to an over-action of the gland. In cases of acromegaly the 

 tumour is generally an adenoma, i.e. an enlargement of the ordinary gland 

 tissue. Total extirpation of the pituitary body is generally followed by 

 death within a few days, death which cannot be attributed to shock or any 

 accidental features of the operation. One must regard the pituitary there- 

 fore as essential to the maintenance of life. It has not been possible by 

 transplantation to replace a removed pituitary body, since the transplanted 

 organ has hitherto always undergone degeneration. In a certain number 

 of cases animals, especially if young, have survived extirpation of the 



