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Mr. J. S. R. Russell. The Abductor and [Mar. 31 r 



the case of those instances in which it was necessary to allow the 

 animals to live for three weeks, for the study of the degenerations 

 which followed section of certain parts of the nerve. In the latter 

 case the operation, which was always of the most trivial character, 

 was performed under strict antiseptic precautions, and the small 

 wound afterwards treated antiseptically. In every case the small 

 wound healed by immediate union. The animals were narcotised in 

 these, as in the other, experiments, and at the end of three weeks 

 death was produced by means of an overdose of chloroform. 



Tracheotomy was performed in every instance (except when the 

 animal was to be allowed to live after the operation), a glass cannula 

 being inserted into the trachea. A short rubber tube connected the 

 free end of the cannula with a glass funnel, through which the anaes- 

 thetic was administered during the remainder of the experiment. 

 The trachea was then completely divided transversely above the 

 point at which the tube had been inserted. A window was cut from 

 the upper portion of the divided trachea and raised gently, so as to 

 give a full view of the larynx, as seen from below, without producing 

 the least traction on the parts, which might disturb their normal play 

 of movement.* 



One or other of the recurrent laryngeal nerves was next exposed, 

 separated from the loose connective tissue which surrounds it, and a 

 ligature passed round the trunk of the nerve at the lower .part of the 

 neck. The nerve was then divided on the proximal (i.e., bulbar) side 

 of the ligature, and its peripheral end was separated into its com- 

 ponent bundles of nerve fibres, round each of which a ligature was 

 passed and secured. 



In the operation for the production of control results by the de- 

 generation method, the nerve, after being exposed and separated 

 from the surrounding connective tissue, was placed in situ upon a 

 piece of cork, in order to steady it, and one bundle of nerve fibres 

 being carefully separated from the others which compose the nerve, 

 a few millimetres of this bundle were excised. These operations 

 were performed under strict antiseptic precautions, the wounds 

 closed by continuous aseptic silk sutures, and afterwards dressed anti- 

 septically, healing by first intention, tracheotomy not having been 

 performed. 



* In observations of this kind it is absolutely essential to view the larynx with- 

 out traction on the attachments of the cords, since in the dog and the cat traction 

 on the larynx, whether by a ligature directly attached to it, or indirectly by pulling 

 forward the tongue, may most easily produce the appearance of either paralysis or 

 spasm of one Tocal cord where no such condition exists in reality. 



