60 PRACTICAL HISTOLOGY. 



separate, others in groups. (It will be found advan- 

 tageous in examining the object to moderate the 

 illumination by the employment of one of the smaller 

 holes of the diaphragm : in this way the somewhat 

 indistinct outlines of the tissue-elements are rendered 

 plainer, and any details of structure can generally 

 be more readily made out ; this is the case, indeed, 

 with most preparations.) In the separated cells, the 

 conical form may be seen, the cell either tapering at 

 one end to a fine point, which may be bifid, or 

 terminating in a rounded extremity. The general 

 substance of the cell has a faintly granular appear- 

 ance in the fresh condition, without a distinct out- 

 line, except at the larger end, which is bounded by 

 a strongly refracting thickened margin, in which a 

 few faint striae passing from without inwards may 

 with a high magnifying power be made out. Near 

 the centre of the cell is the clear oval nucleus, 

 bounded by a distinct line, and containing generally 

 one nucleolus. Globules of fat of varying size may, 

 if the animal were- killed during digestion, be seen 

 within the cell ; they are recognized by their strong 

 refractive power. 



Of the groups of cells some may occur in which 

 the cells are seen from above ; the collective bases 

 will then present an appearance of polygonal areas 

 intersected by lines of intercellular substance; in 

 other groups, where the cells are seen laterally, their 

 arrangement with regard to one another will be 

 observed. 



Some cells will probably be seen which have 

 acquired a peculiar chalice-like shape, owing to the 

 part of the cell near the free surface having become 

 swollen out, often to the extent of bursting away 

 and destroying the thickened border. These are 

 the so-called u goblet cells." 



The other two portions of tissue will not be ready 

 for examination for some days. That in the iodized 

 serum must be put aside in a cold place, in a well- 

 stoppered bottle. At the expiration of a week a pre- 



