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ESSENTIALS OF ZOOLOGY 



year-old boy measured six feet and one inch and weighed 178 pounds. 

 His mental condition was normal. 



Another condition, known as acromegaly, may result from an over- 

 functional anterior lobe of the pituitary during adult years. The' 

 facial bones enlarge, particularly in the ridges above the eyes, the 

 nose, and the lower jaw, and the soft tissues of the face undergo an 

 overgrow^th resulting in a coarsening of the features. The hands 

 and feet may enlarge, also. The disease may prove fatal if it con- 

 tinues sufficiently long. 



Fig. o9. — A pituitary dwarf at the age of nine and one-half years, compared 

 with a normal child of the same age. (From Zoethout. Textbook of Physiology, 

 The C. V. Mosby Company, after Engelbach.) 



A second hormone secreted by the anterior lobe has a direct in- 

 fluence on the sex organs. This gonadotropic honnone (prolan) 

 stimulates growth and activity of the gonads, the testes and ovaries, 

 and therefore controls the production of the gonadal hormones, which 

 will be discussed later. The absence of gonadotropic hormone results 

 in an atrophy of the testes and ovaries, and the cessation of the pro- 

 duction of the spermatozoa and the ova; its injection increases the 

 activity of the sex organs. 



The posterior lobe of the pituitary also produces more than one 

 hormone, although pituitrin is the one concerning w^hich we have 



