OBSERVATIONS ON STRUCTURE OF CELLS AND NUCLEI. 325 



specimens : — a. Columnar epithelial cells varying somewhat 

 in length and thickness ; they are goblet-cells of the same or a 

 similar character as those represented in figs. 1 and 2. They 

 consist of an upper swollen transparent part, and a lower 

 part more opaque and including the nucleus. The first has 

 lost its cover, the second terminates in a more or less inden- 

 tated, serrated, or truncated manner. In some cells the 

 nucleus lies close to the boundary line of the two parts, in 

 Others there is a longer or shorter mass of protoplasm inter- 

 posed between the two. In the latter .case the cell has a 

 much more graceful form, being relatively less plump in 

 both parts. If the preparation be made by scraping the 

 foregut, we meet also with a few ciliated cells, conical or 

 cylindrical in shape. Most of the ciliated epithelial cells of 

 the foregut, however, present themselves likewise as goblet- 

 cells, the cover with the cilia having been removed.^ 



The columnar goblet-cells mentioned before may be 

 grouped, according to size, in two distinct categories — one 

 comprising the larger, the other the smaller forms. The 

 larger cells belong to the surface, the smaller ones to the 

 ducts of the gland. (Besides cells, which, to all appearances 

 are perfect, there are a good many, Avhich present them- 

 selves only as larger or smaller fragments.) 



b. Flat transparent cells with nuclei somewhat larger than 

 the nuclei of those mentioned above. These cells are met 

 with in groups forming the wall of larger or smaller portions 

 of gland-tubes; when in a group they are imbricated, and 

 being flattened they do not appear conspicuous when thus 

 seen in profile ; their bulky nucleus seems to be the chief thing 

 that attracts attention. It is the nuclei of these cells which 

 show the intranuclear network most splendidly. When these 

 cells are met with isolated and looked at in profile they are seen 

 to be composed of a bulky oval nucleus, to one pole of which is 

 attached a short plump process, to the opposite pole one that 

 is many times longer. Some of these cells are seen only as 

 fragments. 



c. Oval, biconvex, more or less polyhedral, or irregularly 

 shaped cells, consisting of a relatively opaque, or what 

 appears as a granular cell-substance, and including an excen- 

 tric large oval nucleus of the same aspect and size as that of 



1 I may here mention that I know of no better reagent for the demon- 

 stration of goblet-cells than 5 percent, chromate of ammonia. A piece of 

 trachea of a mammalian animal placed fresh in 5 per cent, chromate of 

 ammonia, kept there for twenty-four hours, and treated in the manner above 

 detailed, yields excellent specimens for the study and demonstration of 

 goblet-cells in all different stages between ordinary normal epithelial ceils 

 and bulky goblet-shaped mucus-containing cells. 



