38 EPITHELIUM AND ENDOTHELIUM. 



Finally, there show themselves, here and there, long, conical 

 cells (goblet cells), which, like the first mentioned, run into a 

 long process ; and, in the thicker portion (Fig. 7), areempt}', 

 or contain only a very few granules. The ampullate, or flask- 

 shaped portion of these cells is bordered by a double-con- 

 toured membrane, which, at the basal end, is open, so that we 

 have before us only the empty shell of the cell without the 

 basal lid. Among a number of such cells swimming about, 

 individuals occur in which the open ends of the goblets can 

 be seen, both obliquely and from the surface. In the deeper 

 and thinner part of the cell the protoplasm with the nucleus 

 is, in most cases, still present, as represented in the figure. 

 In a few examples part of the cell (Fig. 76) is torn off, so that 

 an empty funnel remains behind, in the extreme apex of which 

 a small bit of protoplasm remains. If we look over a series 

 of preparations we shall certainly find examples in which the 

 complete lid, or a portion of it, remains attached at one point 

 only of the circumference, and floats freely otherwise. The 

 appearances show that these goblet cells are nothing more 

 than products of changes which have occurred in the ordinary 

 conical ciliated cells. In the description of the epithelium of 

 the intestine we shall again have an opportunity of referring 

 to these cells. 



Non- Ciliated Cylindrical Epithelium. For the in- 

 vestigation of this form we use the epithelium of the papilla' 

 of the tongue of the frog, and that of the intestinal canal of a 

 mammal, either in the fresh condition or with the aid of re- 

 agents.* From the dorsal surface of the frog's tongue a minute 

 portion is snipped with curved scissors, transferred by means 

 of a needle from the scissors on to a glass slide, and then, 

 either covered without addition, the glass being pressed lightly 

 down, or mounted in a drop of serum, or of half per cent, solu- 

 tion of common salt. The specimen must be examined with 

 high powers (as, e. #., Hartnack's No 10 immersion). We see 

 the numerous, thin, conical papilla 1 , both from above and in 

 profile ; the latter especially at the borders of the preparation. 

 A papilla seen in profile exhibits on its surface a beautiful 

 mosaic of pale cells, composed of finely granular protoplasm, 

 marked off by sharp clear-shining lines of interstitial substance. 

 If we fix our attention upon the borders and apices of the 

 papilhe, we may convince ourselves that the mosaic is only the 

 surface view of the conical or cylindrical cells, which cover and 

 surround the papillae. Here and there we may easily perceive 

 that these cells are coarsely granular, and that each contains a 

 clear oval nucleus. Such coarsely-granular cells increase in 

 number after the preparation has been mounted some time. 

 W may mention that the cylindrical cells around the bases of 

 the papillae are generally ciliated. 



