42 PHYSIOLOGY CHAP. 



and microscopic) on fowls, buffaloes, oxen, rabbits and guinea- 

 pigs, concluded that there is an intimate relation between the 

 hypophysis and the sexual glands (testicles, ovary), which, as we 

 shall see elsewhere, are also the seat of an important internal 

 secretion. 



He found in castrated animals that removal of the testicles or 

 ovaries led rapidly to hypertrophy and hyperplasia of the pituitary 

 body, which showed histological modifications indicative of func- 

 tional hypertrophy. If the castrated animals are treated by 

 organo-therapy with the sexual glands, the irritative phenomena 

 of the parenchyma of the hypophysis are 

 reduced and eventually disappear. 



In a second series of experiments, Fichera 

 (1905) destroyed the hypophysis in fowls by 

 a new method of operating. He found in a 

 number of experiments, confirmed by micro- 

 scopic examination, that this organ was not 

 indispensable to life. Animals that survived 

 its total destruction merely exhibited an arrest 

 of development, particularly as regards the 

 skeleton. 



Gemelli has recently obtained almost 

 identical results. 



Cerletti (1906 - 8), studying in young 

 guinea-pigs, rabbits, dogs, and lambs the effect 



o. 9.- R i g ht kidney and on somati c g row t h of continuous injection of 



suprarenal body of a fuii- extract of lamb s hypophysis, showed that 



?i?w. n (A?ien US Thonfs r n.) this substance particularly affects the de- 



vein^ssSn* 1 SI"!? *r ve lP m ent of the skeletal system, although 



foetai kidney ; v, renai in an opposite SQnsQ to what might be expected 



artery and vein emerging f _r, -, . . TT A 



from hiiium ; ., ureter, irom the preceding experiments. He con- 

 cluded from his observations that persistent 

 dosage with pituitary extract retards the growth of the body in 

 general, as shown most deleteriously for the skeletal system, where 

 the activity of the connecting cartilages (delay in lengthening of 

 long bones) is conspicuously diminished, while the activity of the 

 periosteal ostogenic function (increased development of depth of 

 epiphyses and diaphyses) is, on the contrary, augmented. Control 

 animals treated with extracts of other organs (thyroid, muscle) did 

 not exhibit similar changes. 



The results of these new experiments indicate that the hypo- 

 physis is a gland of internal secretion, serving in some way to 

 excite or regulate the metabolism of the body and the development 

 of its various organs, particularly of the skeletal system. While 

 too indefinite to represent an exact theory of the function of the 

 hypophysis, this view is, on the other hand, supported by clinical 

 observations on acromegaly and gigantism, which are often, if not 



