204 THE OLFACTORY ORGAN, BY PROFESSOR BABUCHIN. 



or brownish pigment in their interior. Chloride of gold stains 

 them of a deep black colour. Towards the excretory duct the 

 epithelium assumes a more polygonal form, and becomes less 

 granular. The excretory ducts finally reach the surface between 

 the elements of the next following external layer (fig. 338). 

 The orifice sometimes opens at the bottom of a funnel-shaped 

 depression of the membrane. Amongst the lower animals, as 

 in the Frog, it may be very easily demonstrated that the ex- 

 cretory duct is lined, from its commencement to its termination 

 on the surface of the mucous membrane, with smaller cells. 

 Immediately in front of the orifice slender epithelial cells are 

 situated, which are elongated in the direction of the axis of the 

 excretory duct. 



At the point where the olfactory region passes into the ordi- 

 nary mucous membrane, the glands become fewer in number, 

 and ultimately vanish altogether, being replaced by the ordi- 

 nary mucous glands. According to Kolliker, even in the 

 olfactory region of the human subject, instead of the just- 

 described glands, we meet only with the ordinary mucous 

 glands. Schultze, however, considers that in Man they pro- 

 perly constitute a transitional form, and resemble in appearance 

 Meibomian glands.* 



In Fishes, the glands are entirely absent, but are replaced by 

 numerous cells. 



The glands are separated from one another by ordinary con- 

 nective tissue, which is continuous on the one hand with the 

 periosteum, and on the other extends as far as to the epithe- 

 lium. I have not been able to discover the basement mem- 

 brane described by Hoffman. The appearance of a membrane 

 is caused by the contour line of the connective tissue in contact 

 with the epithelium. Both here and in the deeper layers of 

 the connective tissue are many fusiform cells provided with 

 processes, and especially in the lower animals, containing black 

 pigment. M. Schultze has also observed free masses of pig- 

 ment, as well as pigment cells, in the higher animals. Lastly, 

 imbedded in the connective tissue are vessels and the ramifica- 



* More recently, Schultze (5) has observed acinous mucous glands in 

 the olfactory region of Man. 



