8 S. B. VINCENT 



Ostroumow a good paper in 1895. The same year Messenger had 

 a very brief article. Botezat put out two careful studies in 1897 

 and 1902, while some of the more recent contributions are those 

 of Szymonowicz ('09), and Tello ('05). 



In the limits of this paper it is impossible to do more than 

 mention a few of the many studies, but some of them will be 

 referred to for matters of detail in the discussion which follows. 



III. METHODS OF STUDY 



The grosser structure of the nerve supply of the tactile hair 

 may all be seen in a careful dissection. After hardening the 

 head in 10 per cent formaline for a few days, if the skin be cut 

 posterior to the vibrissae and slipped down over the snout until 

 the hairs are reached, the follicles appear, as they are torn away 

 from the subcutaneous tissue, projecting from the epidermis. 

 The branches of the facial nerve are in sight lying over the 

 strong masseter muscle. If the anterior portion of this muscle 

 be now carefully cut away, the sensory nerve will be exposed as 

 it lies directly upon the bone. This nerve may now be followed 

 even to the divisions entering each separate follicle. 



The microscopic studies in this work were made from sections 

 of degenerated nerves stained by the Marchi method, normal 

 tissue stained with osmic acid, by Cajal's silver nitrate method 

 and by Bielschowsky's variation of the same; but the intra- vitam 

 methylen blue method proved the most satisfactory of all. The 

 process adopted with this stain was that described by J. G. 

 Wilson in The Anatomical Record, 1910 (vol. 4, no. 7). 



IV. INNERVATION 



General description. The large sensory portion of the fifth 

 nerve emerges from the Gasserian ganglion in three divisions, of 

 which we are here only concerned with the second, the superior 

 maxillary. This passes through the fissura spheno-orbitalis and 

 then runs along in the infra-orbital groove and while there 

 branches are given off to various parts of the mouth, pharynx 

 and nostrils; but the infra-orbital branch in which we are inter- 



