Mr. Shaw nn the Facial Nerves. 235 



If we compare the anatomy of the facial respiratory nerve, 

 in the various classes of birds, we shall find its distribution to 

 he analogous to that of the same nerve in the different tribes of 

 quadrupeds. In the game-cock, a few branches of the nerve 

 pass to the loose skin under the jaw, which is dilated in crow- 

 ing, the greater number being distributed on the muscles of the 

 neck, which causes the elevation of the feathers when he puts 

 himself in an attitude for fighting. But in the duck, which, 

 when enraged, has little or no power of expression, the same 

 nerve is not larger than a cambric thread, and passes only to 

 the skin under the jaw. 



The effect upon the muscles of the face, produced by cutting 

 the facial respiratory nerve, is in the ratio of the intricacy of 

 the distribution of the branches, and according to the proximity 

 of tiie part cut, to the origin of the nerve from the brain. 



I cannot detail any examples of the effect of cutting this 

 nerve in man, for, though I have witnessed operations where it 

 was done, yet, as they occurred before I was acquainted with the 

 facts now established, I did not take notes of the consequences 

 which ensued. However, I shall presently detail cases where, 

 by disease or accident, the whole nerve in some instances, and 

 part of it in others, has been injured. In those cases the symp- 

 toms very nearly corresponded with the phenomena presented, 

 when the whole, or only a part, of the nerve has been divided 

 in animals. 



About four months ago, I divided the left facial respira- 

 tory nerve of the most expressive monkey I could find in the 



mass of ilif Irun^'. The rorlio Dura bucame quickly diniiiilshcd in size, 

 as it g;ive off its Ijraiiches in great profusion to the muscles : but the Vlli. 

 was continued down, as a very large nerve, to nearly (he extremity of the 

 trunk ; in ihis respect resembling the nerves to the fingers in man. On 

 making sections of the proboscis, near its extremity, a great number of 

 these nerves were seen in ita substance. 



A few branches of the Portlo Dura ran to the valvular apparatus in the 

 tipper part of the trunk ; but. this peculiar structure was supplied prin- 

 cipally by a branih from the Vlh. i>air, which winded round under the 

 oibil 



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