THE TESTICLE AND THE OVARY 325 



the results of testicular transplantation or the injection of testicular 

 extracts. Other instances of the effects of castration are briefly 

 referred to by Darwin.'- 



Secondary sexual characters, however, are not always correlated 

 with the essential organs of reproduction. Por example, castration 

 in the horse does not arrest the development of the withers — the 

 gelding, in this respect, resembling the stallion rather than the mare, 

 in which the withers are lower.^ 



In Arthropods the correlation between the secondary sexual 

 characters and the generative glands appears to be far less close than 

 it is among Vertebrates. Thus, Oudemans ^ showed that the removal 

 of the testes from the male caterpillar of Ocneria dispar had no 

 influence on the development of the secondary male characters, these 

 being normal. Kellogg* performed a similar experiment on the 

 caterpillar of the silkworm moth and obtained a like result. Crampton ^ 

 grafted the heads of caterpillars of one sex upon the bodies of 

 individuals of the opposite sex, and found that the generative organs 

 had no influence upon the development of the secondary sexual 

 characters of the transplanted heads. Moreover, Meisenheimer ^ 

 found that in caterpillars artificially made hermaphrodite (by trans- 

 planting ovaries into males or testes into females) the original males 

 always developed into butterflies with typical secondary male 

 characters in spite of the fact that living ovaries were present, while 

 the original females always developed into normal female butterflies. 

 The sexual instincts were also unmodified by the presence of the 

 grafted gonads. With castrated or spayed individuals into which 

 gonads of the opposite sex were successfully transplanted the effects 

 were similar, the somatic characters of the original sex being 

 unmodified.'^ Eegen* who removed the gonads from larval crickets 



1 Darwin, loc. ait. Sellheim {Beitrcige zwr Gehurtshiilfe v/nd Qynak., vol; i., 

 1898, and vol. ii., 1899) states that there is an increase in the size of the skull, 

 pelvis, and leg-bones in castrated cocks. According to Berizowiski {Arch. 

 Zellforsah., vol. ii., 1911), castration in mice causes elongation and broadening of 

 the cells of the intestinal epithelium, but this would seem to need confirmation. 



2 Wallace, Farm Live- Stock of Great Britain, 4th Edition, London, 1907. 

 Williams (W. L.) says there are no sexual differences in the bones of the pelvis 

 of the horse {Vetei-inary Obstetrics, New York, 1917). 



' Oudemans, " Falter aus Oastraten Eaupen," Zool. Jahrhuchm; vol. xii., 1899. 



* Kellogg, "Influence of the Primary Reproductive Organs on the Secondary 

 Sexual Characters," Jour, of Exp. Zool., vol. i., 1904. 



^ Crampton, "An Experimental Study upon Lepidoptera,'' Arch.f. Entuicl-.- 

 Mechanik, vol. vii., 1898. 



" Meisenheimei', Experimentelle Studien zur Soma- und Gesohlechts-Difer- 

 enzierung, Part I., Jena,- 1909. 



' Kopec, "Nochmals iiber die Unabhangigkeit der Ausbildung sekundaren 

 Geschleohtscharaktere von den Gonaden bei Lepidopteren," Zool. Anz., vol. xliii., 

 1913. See also Kammerer, loc. cit, 



8 Eegen, "Kastration und ihre Folgerscheinungen bei Gi-ylhts campestris," 

 Zool. Anz., vols, xxxiv. and xxxv., 1909 and 1910. 



