Ch. X] 



ISOLATION OF TISSUE ELEMENTS 



331 



that the cells and fibers may be separated from one another, and at 

 the same time the cells are preserved. In fixing and hardening, on 

 the other hand, the cell cement, like the other parts of the tissue, is 

 made firmer. In preparing the isolating solutions it is better to 



7 



I 



-A 



Fig. 196, 197. Shellvial and Comstock, Bent-neck Specimen Bottle. 



Fig. ig6. Shellvial with turned lip. One can have almost any size and length 

 desired. Those of 22 X 65 mm. and 30 X 90 mm. have been found most useful. 

 The larger ones are excellent for staining single slides or pairs. 



Fig. 197. The Comstock, bent-neck specimen bottle is very useful for keeping 

 small animals straight. 



dilute the fixing agents with normal salt solution than merely with 

 water (§ 584). 



§ 515. Example of isolation. — Place a piece of the trachea of a 

 very recently killed animal, or the roof of a frog's mouth, in formalde- 

 hyde dissociator in a shell vial or glass box. After half an hour, up to 

 two or three days, excellent preparations of ciliated cells may be 

 obtained by scraping the trachea or roof of the mouth and mounting 

 the scrapings on a slide. If one proceeds after one hour, probably 

 most of the cells will cling together, and in the various clumps will 

 appear cells on end showing the cilia or the bases of the cells, and 

 other clumps will show the cells in profile. By tapping the cover 



