Mr. Shaw un the Facial Nerves. 241 



The rudiments of the Vth may be discovered in the lowest 

 classes of animals. If a feeler of any kind project from the head 

 of an animal, be it the antenna of a lobster, the moustache of a 

 phoca, or the trunk of an elephant, it is a branch of the Vth 

 which supplies sensibility to the member, and regulates the 

 voluntary actions of its muscles. Thus it may be compared to 

 those nerves in man, which pass to the muscles of the arm, and 

 to the tips of the fingers. 



But this nerve is also, in the greater number of animals, con- 

 nected with the organ of taste — and consequently it is very 

 large ; its magnitude being in proportion to the size of the 

 apparatus connected with mastication and taste. Thus, in 

 the lower scale of animals, the nerve is much larger in propor- 

 tion than in man ; indeed, its size, compared to that of the 

 Poriio Dura, may give us a better estimate of the comparative 

 degree of the power of expression, than can be deduced from any 

 other fact of anatomy. A good example is afforded in the 

 goose or duck. In the latter bird, the six branches of the Vth, 

 when laid together, form a mass equal in size to that of the 

 largest nerve in a man's arm ; while all the branches of the 

 Portio Dura would not form a nerve larger than a common 

 sewing thread. 



In the cat, and in the hare, the branches of the Vth pass not 

 only to the muscles, but also into the whiskers ; while the 

 branches of the facial respiratory nerve go past the hairs, and 

 enter into the muscles, moving the tip of the nostril. It is rather 

 difficult to demonstrate the nerves going into the bulb of the 

 hair in these smaller animals, but it is easily done in the phoca. 

 A preparation illustrative of this fact was shewn to me some 

 years ago in Amsterdam, by Professor Vrolich; and in the first 

 number of the Journal dc Physiologic Experimentale, by M. Ma- 

 gendie, there is an account of " les Nerfs qui se portent aux 

 niouHtaches du Phoquc," by M. Audral. This fact of anatomy, 

 which has been denied by some, is farther demonstrated by 

 liie dissection of those animals which have tufts of Iiuir, or 

 whiskers, over the eye. In the American squirrel 1 have traced 



