INTERACTION OF INTERNAL SECRETIONS 247 



one another. Removal of the thyroid causes hypertrophy 

 of the pituitary; disease of the pituitary leads to over- 

 growth of the thyroid. The regulation of the metabohc 

 processes therefore depends upon a balance between the 

 activities of all the internal secretions. The disturbance 

 which follows the absence of one secretion may be due, 

 not directly to such absence, but to the unchecked activity 

 of the secretions which remain. 



