CH. X] 



MOUNTING MICROSCOPIC OBJECTS 



327 



2. A slide is gently warmed and placed on the centering card 

 (fig. 192) and a drop of warmed glycerin jelly is put on its center. The 

 suitably prepared object is then arranged in the center of the slide. 



3. A drop of the warm glycerin jelly is then 

 put on the object, or if a cell is used it is filled 

 with the medium. 



4. The cover-glass is grasped with fine forceps, 

 the lower side breathed on and then gradually 

 lowered upon the object and gently pressed down. 



5. After mounting, the preparation is left flat 

 in some cool place till the glycerin jelly sets; then 

 the superfluous amount is scraped and wiped 

 away and the cover-glass sealed with shellac 

 ( 508). 



6. The slide is labeled. 



7. The preparation is catalogued and safely 

 stored. 



508. Sealing the cover-glass when no cell is 

 used. (A) For glycerin-mounted specimens. The 

 superfluous glycerin is wiped away as carefully as 

 possible with a moist cloth; then four minute 

 drops of cement are placed at the edge of the 

 cover (fig. 193) and allowed to harden for half an 

 hour or more. These will anchor the cover-glass ; 

 then the preparation may be put on the turn- 

 table and ringed with cement while whirling the 

 turn-table. 



(B) For objects in glycerin jelly, Farrants' 

 solution or a resinous medium. The mounting 

 medium is first allowed to harden; then the 

 superfluous medium is scraped away as much as 

 possible with a knife, and then removed with a 

 cloth moistened with water for the glycerin jelly and Farrants' solu- 

 tion or with alcohol, chloroform or turpentine, etc., if a resinous me- 

 dium is used. Then the slide is put on a turn-table and a ring of the 

 shellac cement added. 



FIG. 193. ANCHOR- 

 ING THE COVER- 

 GLASS AND IRRIGA- 

 TION. 



A This is to show 

 the method of an- 

 choring a cover-glass 

 by means of four 

 drops of cement so 

 that it may be sealed 

 on the turn-table 

 without danger of 

 displacing the cover. 



B Method of ir- 

 rigation. A drop of 

 the irrigating liquid 

 is put on one side of 

 the cover-glass and 

 a piece of absorbent 

 paper on the other. 

 As shown by the 

 arrow the liquid is 

 drawn through. As 

 it spreads more or 

 less on both sides all 

 degrees of the reac- 

 tion produced by the 

 liquid can be found 

 in the same prepara- 

 tion. 



