98 



SMELL, TASTE, ALLIED SENSES 



FIG. 24. Epithelium from the 

 vomero-nasal organ of the sheep 



Brunn's observation that the vomero-nasal sense cells 

 were directly connected with nerve fibers, but he also 

 pointed out that in the Jacobson organ of the foatal rab- 

 bit free-nerve terminations occurred. These free termi- 

 nals in some instances reached the receptive surface of 

 the epithelium where they ended in slight knobs. Similar 

 endings were recorded for the 

 rat by Bamon y Cajal (1895). 

 Von Lenhossek was unable to 

 decide definitely whether these 

 terminals belonged to the olfac- 

 tory or to the trigeminal nerve. 

 Nor is this question definitely 

 settled now, though, judging 

 from the conditions met with 

 in the olfactory organ of 

 the nose, it is highly prob- 

 able, as Bead concludes, that they belong to the trigem- 

 inal nerve. Admitting this to be the case, the innervation 

 of the vomero-nasal organ would agree in all particulars 

 with that of the olfactory organ proper. It is quite 

 clear from the studies of Brookover (1917) on the ner- 

 vus terminalis as well as from those of Larsell (1918) 

 that the relations of this nerve to the vomero-nasal organ 

 are merely incidental ; the terminal nerve is in no sense 

 especially connected with the organ of Jacobson. 



4. Adjacent Parts. In many of the higher verte- 

 brates the vomero-nasal organ is contained within a more 

 or less complete capsule of cartilage, the Jacobson car- 

 tilage (See Fig. 23). In the cat this capsule, according 

 to Eead, is complete anteriorly and incomplete posteri- 

 orly; in the dog it is incomplete throughout its whole 



showing the receptive cells impreg- 

 nated by the Golgi method. After 

 von Brunn, 1892, Plate 30, Fig. 12. 



