PINEALECTOMY 423 



Izawa performed pinealectomy on 36 chickens ranging from 4 to 5 

 weeks of age, and besides these 1 1 others of the same age and weight 

 as those operated on were used for comparison. Aseptic precautions 

 were taken, and no cases of infection occurred. Most of the experimental 

 animals died shortly after the operation. Only four — three males and 

 one female — survived the operation for any length of time. These were 

 fed under the same conditions as the control animals and the effects 

 observed. Compared with the controls, the pinealectomized animals 

 showed a retarded growth for a few weeks following the operation, but 

 about a month later they grew more rapidly than the controls, their 

 body-weight becoming greater and their legs longer than those of the 

 controls. In the two males whose pineal bodies were completely removed, 

 the rapid development of the comb and the premature crow deserve 

 special notice, and Izawa stated that they gave evidence of sexual instinct 

 31 and 50 days earlier than the controls. There was also a marked increase 

 in the size of the testes. 



In the female pinealectomized bird there was a remarkable increase 

 in the size of the ovary and of the Fallopian tube, the latter showing a 

 great increase in the length of the tube with increase in the width of its 

 ampullary portion, which was described as voluminous, while the Fallopian 

 tubes in the control were not only short but uniformly slender throughout 

 their whole length. 



Zoia and Horrax also report positive results following pinealectomy. 

 The latter states that pinealectomized hens tend to breed earlier than 

 controls of the same age and weight ; on the other hand, Sarteschi reports 

 that pinealectomized hens dislike to copulate. Izawa gives tables showing 

 the exact weight and size of the various organs and parts of the animals 

 experimented on, and of the controls. From the statistical side it should 

 be borne in mind that the results obtained by Izawa, striking as they 

 appear to be, were based on only three cases, two male and one female, 

 and that the controls were individuals matched with regard to age and 

 weight with the experimental animal rather than of average size and 

 weight. 



Positive results following pinealectomy have also been recorded 

 by Urechia and Gregoriu, Hoffmann, Zoia, Clemente, Izawa, and 

 Yokoh in young rats and chickens, namely, general increase in the 

 growth of the body and increase in the size and weight of the 

 genital glands in both males and females. Hoffmann also found in 

 three pinealectomized rats a decided enlargement of the vesicular 

 seminales. 



Horrax, 19 16, experimenting with rats and guinea-pigs, found accelera- 

 tion of spermatogenesis in the pinealectomized animals. 



