XXVIIl] TONGUE. NOSE 219 



cylindrical outer portion, and a much thinner and 

 sometimes branched inner portion. 



The olfactory cell; it has a projecting spherical 

 nucleus, a slender, smooth, outer portion, and a still 

 more slender, rather irregular inner portion. 



The columnar cells surrounded and partially hidden 

 by three, four, or more olfactory cells. 



Probably the granules of the serous glands beneath the epithelium 

 (corresponding to Bowman's glands in the mammal) will be preserved 

 and be very obvious. 



DEMONSTRATIONS. 



1. Vertical section of tongue (rabbit or cat) with 

 blood vessels injected. 



2. Section of the respiratory part of the nasal 

 mucous membrane of a mammal (osmic acid 1 hour, 

 well washed ; hasmatoxylin). Note the ciliated cells, 

 the mucous cells, and the glands. 



3. Section of mammalian olfactory mucous mem- 

 brane (upper part of septum of nose of dog ; Flemming's 

 fluid ; Ehrlich-Biondi stain). Compare with B 1 ; 

 note that the processes of the olfactory cells project 

 very little beyond the columnar cells. 



NOTES. 



What has been said in the Notes to Lesson XXVIT. with regard 

 to hardening and staining the skin holds also for the tongue. 



For circuinvallate papillae the back of the tongue of the calf 

 may be taken. 



Organs similar to taste-buds will be seen in the skin of many 

 fish (piece of punctated skin of head ; Flemming's fluid). 



