34 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Testicular Grafts.— Ed. Retterer {C. R. Soc. Biol, 1919, 82^ 

 1022-5). Testicular grafts have been previously made in amphibians 

 and birds, and it has been noted that the seminiferous tubules continue 

 for some time to form spermatozoa, but that the epithelium gradually 

 degenerates. Mammalian testes transplanted into the peritoneal cavity 

 or underneath the skin show after some time only Sertoli's cells, which 

 multiply by mitosis, or are converted into giant-cells or indifferent 

 epithelium. Testes of rats grafted on the internal surface of the 

 abdominal wall showed degeneration of seminal cells ; the seminiferous- 

 tubules became covered only by a succulent epithelium, and the inter- 

 stitial cells increased in number. Retterer has made grafts of testes or 

 pieces of testes in the goat. Both in the entire testes and in the pieces 

 the only parts that survived were the superficial portions which con- 

 tinued to receive nutritive plasma. The superficial cells that survived 

 changed their structure and mode of development. A few continued to* 

 divide to form small nuclei and the heads of spermatozoa. The great 

 majority were transformed into a mass of coalescent cytoplasm which 

 ended by becoming reticular connective tissue. J. A. T. 



Experimental Degeneration of Testis in Dog. — Albert Kuntz 

 {Anat. Record, 1919, 17, 221-34, 4 figs.). Elimination of the sympa- 

 thetic nerve supply to the testes is followed by degeneration of the 

 seminal epithelium and accompanying hypertrophy of the interstitial 

 secretory tissue. The same degeneration followed in both testes after 

 ligature and resection of the right ductus deferens. The degeneration 

 was similar to that following exposure of the testis to X-rays, or follow- 

 ing a diet deficient in the water-soluble vitamines. J. A. T. 



Innervation of Gonads in Dog. — Albert Kuntz {Anat. Record^ 

 1919, 17, 203-19, 4 figs.). The sympathetic nerves to ovaries and 

 testes pass distally along the ovarian and spermatic arteries respectively^ 

 and enter the organs in more or less intimate association with the blood- 

 vessels or the efferent ducts. The majority of these fibres are derived 

 directly from the sympathetic ramus ascending from the inferior mesen- 

 teric ganglia to the renal plexus. The blood-vessels and all other 

 structures in the gonads which contain smooth muscle receive an 

 abundant sympathetic nerve supply. The evidence available does not 

 indicate a sympathetic nerve supply either to the ovarian follicles and 

 the interstitial secretory tissue in the ovary, or to the seminal epithelium 

 and the interstitial secretory tissue in the testis. J. A. T. 



Sterility of Mules. — W. M. Goldsmith {Amer. Journ. Veterinary 

 Medicine, 1917, June, 1-8, 19 figs.). The mule possesses the necessary 

 reproductive organs and the sex impulse. The early cells of the testis 

 show normal cells with fifty ordinary chromosomes and one sex- 

 determiner. The horse has only thirty-six plus the extra chromosome. 

 It is supposed that the ass has about sixty-five chromosomes. According 

 to Wodsedalek, most of the mule's spermatocytes disintegrate during 

 the maturation division, perhaps because of the marked difference in 



