36 Effie A. Eead 



ioranien (foramen etlimoidale) into the cranial cavity. It passes along 

 the olfactory bulb (bulbus olfactorius) (Fig. 3) cephalad through an 

 opening on the cribriform plate and passes along the upper part of the 

 nasal septum (septum nasi) (Figs. 2, 4, 7, 13, 14), where it divides 

 into the external nasal nerve (nervus nasalis externus) and the internal 

 nasal nerves (nervii nasales internii). The external nasal nerve passes 

 along the sulcus ethmoidalis of the nasal bone (os nasale) and passes 

 out to innervate the skin of the nose (Figs. 13, 14). The internal nasal 

 nerve divides into the median nasal (ramus nasalis medialis), which 

 supplies the septum, and the lateral nasal nerve (ramus nasalis later- 

 alis), which innervates the mucosa of the lateral wall. 



The remaining part of tlie mucosa is innervated by the spheno- 

 palatine nerves (Figs. 1, 3). The naso-palatine branch of this nerve 

 (n. palatinus) was traced along the septum to the canal of the incisors 

 (canalis incisivus). It sends several branches into the middle of the 

 septum (Figs. 2, 4). In dog and cat this .was traced into the vomero- 

 nasal organ (Figs. 2, 4). This nerve was also dissected in man and was 

 traced almost into the organ. The terminal branches were so fine that 

 their complete dissection was not successful. 



Free Terminations of the 5th Nerve Within the Nasal Mucosa. 



von Brunn, 1892, saw free nerve terminations within the nasal 

 epithelium at the border of the respiratory region. According to him 

 these fibers could not be the olfactory axones, as they were much thicker 

 than those. He, therefore, concludes that they are the endings of the 

 Trigeminus. He quotes Cajal as supporting his decision. 



von Lenliossek, 1892, has seen the fibers described by von Brunn, but 

 instead of being thick, as described by that author, those seen by him 

 are finer than the olfactory fibers, varicose and with terminal endings; 

 these did not always reach the free surface of the epithelium. The 

 nerves which are pictured and described by von Lenhossek are like 

 those pictured by Cajal and not of the ordinary much branched appear- 

 ance of a sensory nerve in epithelium, von Lenhossek did not commit 

 himself as to the origin of these fibers. 



RetziuSj, 1892, pictures in the nasal epithelium of the mouse and cat, 

 both in the respiratory and olfactory regions, fine, much-branched nerve 

 fibers, which end free in the epithelium like other sensory nerves. These 

 are varicose, but not always with an end Ivnot. Eetzius wishes to confirm 



