210 THE OLFACTORY ORGAN, BY PROFESSOR BABUCHIX. 



which are likewise intercalated in the epithelial layer, and 

 which call to mind the forked cells of Engelmann. Their form 

 is very various, and is represented in fig. 340, B. They are in 

 immediate contact, by their central extremity, with the sub- 

 epithelial layer, and here frequently break up into very fine 

 short fibrils. Their peripheric extremity does not reach to the 

 surface of the epithelial layer, and is either conically pointed 

 or branched. Their form, moreover, as above mentioned, is 

 very variable, so that in the Proteus, for example, we meet 

 Avith cells that, owing to their ramification, are very similar 

 to the multipolar nerve-cells. 



Lastly, it is not uncommon in young animals, and in the 

 deeper part of the epithelial layer, to meet with round cells, 

 destitute of any processes, which we may no doubt regard as 

 destined to develop into the olfactory and epithelial cells. 



The conducting apparatus of the olfactory organ is composed 

 of the so-called olfactory nerves, which, as is well known, arise 

 from the two bulbi olfactorii, and, according to the animal, 

 either constitute a single nerve trunk, or form several strands, 

 and then ramify in the mucous membrane of the olfactory 

 region. The trunks of the olfactory nerve, which .may be 

 very readily broken up into fasciculi, run either horizontally 

 or obliquely, in the glandular layer. From these trunks nu- 

 merous branches are given off, which, undergoing further 

 subdivision at different angles, run outward to the epithelial 

 layer, and in specimens prepared with chloride of gold may be 

 distinctly followed to its deep surface. On the other side the 

 branches of the nerves run to the base of Bowman's glands. 



The minute anatomy of these nerves has been sufficiently 

 examined by Max Schultze, and has been already discussed at 

 pp. 162, et seq., of the first volume of this work. I am unable, 

 however, to agree with the statement of this observer, that 

 the olfactory nerves contain primitive nerve fibres, which are 

 constructed on the type of those of Remak, that is to say,, of a 

 nucleated sheath of Schwann and fibrillar contents. Max 

 Schultze states that the funiculi of the olfactory nerves split 

 up into fasciculi of primitive fibres, and that in some few 

 animals these fasciculi consist of fibrils, and are enclosed in a 

 nucleated sheath, which he names the sheath of Schwann; 



