No. 3.] PERIPHERAL NERVES. 667 



solution. The catgut used for suturing the nerve was steril- 

 ized for thirty minutes in boiling alcohol. 



In each case the wound was closed by a double set of 

 sutures. The subcutaneous connective tissue, which had been 

 divided in cutting down to the nerve, was brought together 

 over the sutured nerve by means of four to six chromatized 

 catgut sutures. The edges of the wound in the epidermis 

 were then united with braided silk and covered with iodoform. 

 It was hoped that, even though the " skin wound" might open 

 in a few days, the connective tissue which formed a covering 

 for the nerve would, in the meantime, have united, and thus 

 retain in place the implanted substance ; this was found to be 

 the case. Now and then several of the silk sutures gave way, 

 but in no instance were the ends of the nerve stumps nor the 

 implanted portion exposed. In those experiments where a 

 segment of a nerve was implanted, this was, in all but two 

 cases, taken from the sciatic of a cat. While the nerve to be 

 sutured in the dog was being exposed and resected, an assistant 

 chloroformed a cat, removed the skin from the posterior sur- 

 face of one of its hind legs, and then thoroughly washed the 

 denuded surface with a five per cent carbolic acid solution. 

 The sciatic was then exposed, exsected, and transferred to the 

 wound in the dog's arm. No attempt was made to stitch the 

 central end of the segment taken from the cat's sciatic to the 

 central stump of the dog's ulnar. The manner of preparing 

 the bone tube and the bundle of catgut threads, implanted in a 

 number of cases, will be described in detail when such opera- 

 tions are mentioned. The irritability of the nerves was tested 

 at the time of examination with induction shocks from a 

 Du Bois Reymond coil, the ordinary wire electrodes being 

 used. The strength of stimulus necessary to produce reflexes 

 or excite contractions of muscles supplied by the nerve under 

 examination was estimated by the distance separating the 

 primary and secondary coil. In all examinations the same 

 battery, induction coil, and electrodes were used, so that the 

 results obtained in the various experiments admit of compari- 

 son. It is, of course, understood that much reliance cannot be 

 placed on such comparisons, as the strength of the shocks 



