922 R. G. HOSKINS 



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by clinical observations. Rogowitsch (1889) first noted that after thy- 

 roidectomy hypertrophy takes place in the hypophysis. In explanation 

 of this condition, he propounded the theory that, in case of need, the 

 hypophysis can assume, in greater or less degree, the thyroid function. 

 Stieda (1890) repeated Rogowitsch's experiments upon 7 rabbits. He 

 described the hypophyseal hypertrophy that resulted as due to an increase 

 in the number of "chromophobe" cells of the anterior lobe with a vacuoliza- 

 tion of their protoplasm. The chromaphil cells were not demonstrably 

 affected, and there was no evidence of increased colloid formation. Tizzoni 

 and Sentanni (quoted by Delille) performed thyroidectomies upon 2 

 dogs and noted 1% and 4 years respectively after the operation results 

 similar to those of Rogowitsch, except that there was a marked diminution 

 of chromophobe cells, Gley (a) (1892), Leonhardt (1897), and Hofmeis- 

 ter (1892) obtained similar hypertrophy with rabbits, as did Alquier 

 (1907) in the dog, and Thaon (1907) in the ram. Confirmatory results 

 have been reported by Horsley, v. Eiselsberg, and Lusenna. Cimoroni 

 (1907) studied the effects of thyroidectomy in the hypophyses of dogs and 

 rabbits. He noted, not only gross hypertrophy, but also cytological changes 

 which he regarded as evidence of enhanced secretory activity. Herring 

 (a) (1908) failed to confirm the observations of these different investiga- 

 tors that the anterior lobe hypertrophies following thyroidectomy, but he 

 did note evidence of increased activity in the pars intermedia. Hoskins and 

 Morris (1917) found no changes in the hypophysis of frog larvas follow- 

 ing thyroidectomy. Rogers (1918), and later Hoskins and Hoskins (d), 

 however, obtained positive results. The anterior lobe of the hypophysis 

 reached a larger size, in proportion to body-length, in thyroidectomized 

 than in normal tadpoles, as well as young, sexually mature frogs. More 

 recently, the effects of thyroidectomy in puppies and young dogs have been 

 restudied by Kamo. When the animals were sacrificed 1% to 5 months 

 after the operation, marked hypertrophy of the hypophysis, even to more 

 than twice the normal size, was noted. The anterior lobe chiefly was af- 

 fected. Trautman (1916) made an extensive study of the effects of thy- 

 roidectomy on the hypophysis of 30 goats, He noted marked alterations in 

 all three parts of the gland, but regarded them as mainly of a degenerative 

 type. His report includes an extensive summary of the literature. 



Various clinical observers, for example Sharp (1916) and Mott 

 (1917), have observed signs of overactivity in the hypophysis in condi- 

 tions of spontaneous thyroid deficiency. 



The evidence, on the whole, indicates rather definitely that thyroid 

 deficiency leads to hypertrophy and secretory activity upon the part of the 

 hypophysis. There is some disagreement, however, among observers 

 as to the degree to which different portions of the hypophysis are affected. 



The effects of experimental hyperthyroidism upon the hypophysis 

 have been much less extensively investigated than have the effects of 



