ON VASOLIGATION, ETC. 281 



Vasoligation, Etc. — Report of Committee (Dr. F. A. E. Crew, Chairman : 

 Mr. J. T. Cunningham, Secretary ; Professor J. S. Huxley) for 

 the experimental Investigation of the Effects of Vasoligation, Crypt- 

 orchidism, Grafting, etc., on the Seminal Tubules and Interstitial 

 Tissue of the Testes of Mammals. 



The report submitted last year dealt with artificial Cryptorchidism and ligature of 

 the vas deferens in the rabbit. The present Report contains some more experiments 

 of the same kinds on the rat and cat, but describes chiefly experiments on the ligation 

 of the vasa efferentia in tame rats, mostly of the albino variety. 



It was desirable to carry out experiments on the ligature of the vas deferens in 

 some animal in which the testis could not be withdrawn into the abdomen by the 

 animal, either voluntarily or by reflex action, as in rodents, and the cat was selected 

 for the purpose. By this means all doubt whether the result was due to the ligature 

 or to the alteration of the normal relations of the testis to the scrotum, in other words 

 to a partial or complete, temporary or permanent, dislocation of the testis into the 

 abdominal cavity would be eliminated. It is difficult to find in the literature definite 

 descriptions of the condition and relations of the inguinal canal in different mammals, 

 but it is stated in Quain's Anatomy that the canal is actually closed only in the human 

 species, in adaptation to the erect attitude. Dissection of a male cat showed that the 

 cavity of the scrotum is connected with the abdominal cavity by a long narrow canal 

 lined by peritoneum, and passing beneath the skin over the ventral surface of the 

 pelvic girdle. The lumen of the canal was so narrow that only an ordinary seeker or 

 probe could be passed through it, and there was no possibility of the testis passing 

 into it or through it. There was no muscular layer in the wall of the canal, and very 

 little muscle in the wall of the scrotum itself. 



Ligature of the vas deferens in the Cat. 



Urethane was tried as an anaesthetic for cats, but proved very unsuccessful. One 

 cat injected with this drug died after the operation without recovering consciousness, 

 another died during the operation. A successful operation was carried out by using 

 chloroform and ether as anaesthetic. The scrotum on the right side was opened, the 

 vas deferens ligatured in two places, and a piece between the ligatures cut out. The 

 animal recovered quickly and lived in good health until it was killed with chloroform 

 104 days after the operation. The end of the vas next to the operated (right) testis 

 was found to be closed, and the spermatic blood vessels uninjured. Abundant active 

 sperms were obtained from the cauda epididymis of the left side. Sections of the 

 operated (right) testis showed perfectly normal spermatogenesis. 



The post-operative period stated by Bouin and Ancel to be sufficient to produce 

 complete degeneration of the seminal tubules after ligature and vasectomy in the 

 guinea pig was 102 days. In this experiment on the cat no injurious effect was 

 visible after the lapse of 104 days. The epididymis of the operated side, as in similar 

 experiments on the rabbit carried out last year, was distended with semen, its diameter 

 being twice as great as that of the normal on the unoperated side. The testis and 

 epididymis of the operated side showed slight congestion of the blood vessels, having 

 a darker colour than the normal from this cause. This experiment confirms the 

 evidence of the previous experiments on rabbits, and proves that ligature and 

 resection of the vas deferens does not cause degeneration of the seminal tubules with 

 cessation of spermatogenesis in the cat within a period of more than three months. 



No further experiments were made on cats, as it was desired to test the effects 

 of ligature of the vasa efferentia for comparison. For these experiments, as stated 

 above, with one exception, albino rats were used. Complete descriptions of the 

 position and relations of the vasa efferentia in the lower mammals have not been 

 available until quite recently, but for man they are given in standard text-books of 

 anatomy. In most cases (e.g. rabbit and cat) the epididymis and testis are so closely 

 attached that the vasa efferentia cannot be distinguished by inspection of the surface, 

 and it did not seem possible to pass a ligature round them with certainty. In the rat, 

 Miss Gertrude van Wagenen, of the University of California {Anat. Record, Philadelphia, 

 Vol. 27, 28, 1894, p. 189), has stated that the ducts are sufficiently discrete to permit 

 complete ligation without interfering with the blood supply to the testis. She states 



