338 THE PHYSIOLOGY OF REPRODUCTION 



secondary sexual characters of animals are usually arranged symmetri- 

 cally. The effect produced ly < mo -sided castration is general rather 

 than local, and the operation has little or no influence in destroying 

 the symmetry of the sexual characteristics (c/., however, Fowler's 

 statement about t'allo\\ deer, which appears to he exceptional). It is 

 probahle, therefore, that 1'fliiger is correct in supposing that the 

 internal secretion, of the testis acts as a direct stimulus upon the cells 

 of the frog's arm and so induces the development of the sexual pad 

 and the hypertrophy uf the muscle. 1 



Meisenheimer 2 has confirmed the resultsof Nnssbaum's experiments 

 on castration and testicular transplantation in the frog, hut Smith 

 and Schuster, 3 who have repeated the experiments, while admitting 

 that the castration eil'ect occurs, were sceptical about the efficiency of 

 the grafts, their own transplantation experiments being negative. 

 The latter authors t'urtlier criticise Nussbaum and Meisenheimer's 

 conclusions, stating that " the effect of castration, except actually 

 during the breeding season, is to make the papilla 1 , on the thumb-pads 

 remain essentially in the condition they were at the time of castration." 

 Mfisenheimer's claim to have induced hypertrophy as a result of 

 ovarian transplantation they regard as quite unproved. 



According to Kammerer 4 the pad can develop in the breeding 

 season in Alytes in individuals previously castrated. 



There is some evidence to show that, after one-sided castration, 

 the remaining testis is capable of undergoing a compensating 

 hyi>ertrophy, 5 and according to Ancel and Bouin and others there 

 is a compensatory enlargement of the interstitial gland. Lipschiitz 7 

 has thrown some doubt on this conclusion, pointing out that a very 

 small fragment of testicular tissue suffices for the development and 

 maintenance of the sexual characteristics, as shown both by himself 



See also Nussbaum, "Hoden und Brunstorgane, etc.," Pilii<j,-r'x Arch., 



cxxvi., 1909. For further references to the literature of testicular trans- 



plantation, see Boruttau, " Innere Sekretion," in NagePs Handbuch der Physiologic 



* Merucken, Braunschweig, 1906 ; and Harms, ExpenmenteUe Untcrsuchungen 



e tnnr. ,/,, /\Y/,/,./,-/Vx/'//, .fena, ]!! I. 



Mewenheimer, " Ueber die Wirkung von Hoden- und Ovarial Substanz 

 die Sekundaivn < kchlecht*merkmale defc Frosches, ;: /.,>l. .U:., vol. xxxviii., 



I-*! 1. 



Smith and Sehu>t.-r. "Studies in the Experimental Analysis of Sex," 

 t8, \fnar.jtnur. .!//,,-. Science, vol. Mi., 1912. 



Kammerer, " Vererhimg Krzwungener Formveriinderungen, etc.," J/v//. 

 f. Awfin.*.-.!/, ,/,.///, v ,,l. xiiv., |ti!i. 



* ^'bbert "Beitrag,. /,- kompensatorischen Hypertrophie, etc.," Arch. /. 



JSntei" ,7- ? vol. i., IS'.M. 



Bouin and Ancel, Kecherches sur le R61e de la Glande Interstitielle, etc.," 



vol. cxxxvii.. |'.i : "in Claude Inst., etc." C. It. de 



I. cxxxvnu, 1904 ; "De la Glande, etc.," Jour, de Phys. ct Path., 



Lipscjuitz, Ottow Wagner, and Bormann, "On the Hypertrophy of the 



ln the Testicle of tbe 



