1 64 GROWTH 



dom later. Professor Brody has shown that the period of adoles- 

 cent growth in the human is coincident with rapid growth. The 

 pituitary is more active during this age. We can scarcely escape 

 the conclusions, that gigantism is overgrowth induced under the 

 stimulating control of the hormones of the pituitary. 



There is another type of abnormal and excessive growth, a 

 type which begins in adulthood when a man has passed the nor- 

 mal span of years of active growth in stature. The long bones 

 do not take much part in this form of the growth, but the bones 

 of the skull, cheeks, jaw and face, and chest are strongly af- 

 fected, producing great enlargement, this change in the head is 

 known as acromegalia. As early as 1886 Mane associated this 

 growth with disease of the pituitary. Cushing's 16 operative and 

 experimental work (1909) has become classic. Cushing records 

 a series of pictures of a young man who at about the age of 25 

 first noticed an increase in the size of his head and facial out- 

 lines. At the age of 40 the facial features were coarse, heavy, 

 and excessively overgrown. Mild examples are more or less 

 common among persons from 35 to 50 years of age. Gigantism 

 and acromegaly are examples of stimulation to growth by over- 

 activity of the pituitary by the anterior pituitary hormones. 

 These are clear cases of hyperpituitaryism. 



Cushing operated the anterior pituitary lobe in young dogs 

 and noted that these failed of full development and remained 

 infantile. He transplanted anterior lobe with demonstrated im- 

 provement in growth. Long and Evans, 17, proceeding on the 

 known fact that transplanted tissues are resorbed, prepared sus- 

 pensions of finely divided anterior lobe which they repeatedly 

 injected into the peritoneal cavity of growing young rats. They 

 obtained giants of double the size of normal litter mates. 



That this lobe influences growth of other than skeletal tis- 

 sues has just been brilliantly demonstrated by Smith and 

 Engle. 18 It has long been known that certain endocrine glands 

 have a functional interdependence. For example, the relative 

 size of the pituitary, the thyroid, and the suprarenal varies each 



