34 



A N A T M V A N I) PHYSIOLOGY OF 



Experiment.— This experiment was designed to be a repetition of the plan of the 

 last one, but, in dividing the hyoid bone to reach the nerve at the middle line, the 

 saw, accidentally carried too deep, touched the membrane on which runs the nerve. 

 Section of the recurrents followed with the usual negative result. Section of the 

 right superior laryngeal nerve produced paralysis in the right glottic lip. If our 

 former view be correct, then in the present case Ave must have cut the communi- 

 cating branch with the saw. In the above experiments, the sections and results 

 may be thus stated: — 



1. Section of interlateral communication between the two superior laryngeal 

 nerves; glottic respiratory motions as usual. 



2. Section of both inferior laryngeal nerves; glottic respiratory motions as usual. 



3. Section of right superior laryngeal nerve; paralysis of right lip of glottis. 



Experiment.— Snapper, weight four pounds. We cut first the two inferior laryn- 

 geal ; next we divided the right superior laryngeal. The glottic movements were 

 still perfect. One nerve was sustaining unimpaired the whole ordinary motions of 

 the glottis in respiration. Indeed, the closest scrutiny failed to discover in its action 

 any departure from the condition of health. Lastly, we sawed through the hyoid 

 bone, glottic acts still regular. Then with a hook we lifted the nerve and divided 

 it. Instantly a respiration followed, but the right glottic lip was now motionless. 



Order of section, and results: — 



1. Section of both inferior laryngeal nerves. 



2. Sect ion of right superior laryngeal nerve ; after which the glottis moved in 

 respiration as usual. 



3. Section of median intercommunicating nerve ; paralysis of right glottic lip. 

 Experiment. — This turtle had been used for other purposes, and had undergone 



an hour before section of the middle cervical spine. The respiratory motions of the 

 breast-box had ceased, but at intervals the glottis opened and closed with normal 

 regularitv. The trachea was divided, and with it both recurrent laryngeal nerves. 

 Next we cut the interlateral communicating nerve. The glottic acts still remained 

 perfect. Lastly, we exposed the left superior laryngeal nerve, and divided it, causing 

 instant paralysis of the left glottic lip. 

 Order of section, and results: — 



1. Section of both recurrent laryngeal nerves. 



2. Section of communicating branch ; glottic acts perfect. 



:'.. Section of left superior laryngeal nerve; paralysis of left glottic lip. 

 \s further illustration, we give in brief the order of section and results in two 

 box-turtles. 

 /•.'./•/» rinu ni. 



1. Section of both inferior laryngeal nerves; glottic motion perfect. 

 ■2. Section of right superior laryngeal nerve; glottic motion perfect. 



3. Section of communicating nerve; paralysis of right lip of glottis, 

 t. Section of left superior laryngeal nerve; total paralysis of glottis. 

 Experiment. 



1. Section of communicating nerve. 



2. Section of right superior laryngeal ; glottic acts perfect, perhaps not closing 



