BY DR. KLEIN. 157 



of chromic acid (one-twentieth per cent). The teased prepara- 

 tions must be mounted in glycerin. 



At the edge which unites the dorsal and lateral surfaces of 

 the tongue of the rabbit, a round or oval depression is seen, 

 on the surface of which an arrangement of furrows with inter- 

 mediate ridges are visible to the naked eye. If a vertical sec- 

 tion is made of this part, in a tongue hardened in one-tenth per 

 cent, chromic acid, in such a direction that the plane of section 

 crosses the ridges, a meshwork of trabeculse of striped muscular 

 fibres, in the spaces of which the numerous mucous glands are 

 embedded, can be recognized. The short ducts of these glands 

 rise for the most part vertically, but occasional!}' obliquely to 

 the surface ; always opening into the splits between the ridges. 

 So much of the mucosa as lies underneath the furrows and 

 ridges, contains a great number of non-medullated nerve-fibres. 

 Each ridge is covered with a layer of epithelium which becomes 

 thicker upwards, i. e., towards the arete ; and on either aspect 

 of each ridge, certain bodies are seen, embedded in the surface 

 by which it looks towards its neighbor : to these the term taste 

 goblets (Geschmacksbecher) has been applied. They are, as 

 the term indicates, bell or cup-shaped structures, which are 

 limited by a special layer of flattened epithelium cells, which in 

 profile look spindle-shaped. Into the space inclosed within 

 this layer, there projects from the mucosa a bunch of oblong 

 spindle-shaped cells, which towards their bases appear to be 

 divided. Each contains an oblong nucleus. The forms of the 

 elements just described, and of those which constitute the outer 

 wall or investment of each goblet, should be studied in teased 

 preparations. The circumvallate papillae of the human tongue 

 and of other mammalia exhibit similar structures. 



Organ of Smell. Teased preparations can be obtained 

 by macerating the olfactoiy mucous membrane of the frog 

 or of mammalia in one-twentieth per cent, chromic acid, in 

 Miiller's liquid, or iodized serum, or perosmic acid. The whole 

 of the head of the frog, after removing the lower jaw, and 

 opening the nares, is placed in the liquid. In mammalia, the 

 nares can be opened in the middle line, after which portions of 

 the olfactory tract can be removed. For the preparation of 

 sections, the parts must be kept in one-fifth per cent, solution 

 of chromic acid, which must be renewed as often as necessary 

 till the bone becomes soft. In teased preparations it is seen 

 that there is no marked distinction between the ordinary coni- 

 cal epithelial cells and the special spindle-shaped cells, recog- 

 nized as olfactory epithelium : for they are connected together 

 by a continuous series of transitional forms. The most char- 

 acteristic form of the olfactory cells is drawn out at both ends, 

 viz., towards the mucosa into an extremely slender filament, 

 which exhibits granular swellings ; and towards the surface 



