160 



SENSE OF SMELL. 



Fig. 60 



Fig. 61. 



A portion of the Pituitary Membrane 

 of the Nasal Septum, magnified 9 

 times, showing the Number, Sizes. 

 and Arrangement of the Mucous 

 Crypts. 



A portion of the Pituitary Membrane with 

 its Arteries and Veins injected. Magni- 

 fied 15 diameters. 



The natural size of this piece is seen at the 

 bottom of the cut. 



1,1, 1. Orifices of three mucous crypts sur- 

 rounded by veins and arteries. 



Fig. 62. 



means of observation cannot be considered sufficient to enable us to 

 decide this question positively. The nerve has not been traced on the 

 os spongiosum inferius; on the inner surface of the middle spongy bone, 

 or in any of the sinuses. 



The olfactory filaments, according to Messrs. Todd and Bowman, 1 



form a considerable part of the entire 

 thickness of the Schneiderian mem- 

 brane, and differ widely from the ordi- 

 nary encephalic nerves in structure. 

 They contain no white substance of 

 ScTiwann; are not divisible into ele- 

 mentary fibrillae; are nucleated and 

 finely granular in texture, and invested 

 with a sheath of homogeneous mem- 

 brane; and are regarded by those gen- 

 tlemen as direct continuations of the 

 vesicular matter of the olfactory bulb 

 or ganglion; and they "venture to 

 hint," that the amalgamation of the 

 elements of the peripheral part of the 

 nervous apparatus in the larger branches, 

 In acetic acid - Ma ^ nified and probably in the most remote distri- 

 bution, as well as the nucleated charac- 

 ter indicative of an essential continuity of tissue with the vesicular 

 matter of the lobe, are in accordance with the oneness of the sensation 

 resulting from simultaneous impressions on different parts of this organ 

 of sense, and seem to show, that it would be most correct to speak of 

 the first pair of nerves as a portion of the nervous centre put forward 



Olfactory Filaments of the Dog. 



1 Op.cit.,ii. 5-11. 



