XX 11 



To mount in Jelly. — Remove as much .water as possible ; 

 place the slide, coverglass, and jelly in the incubator (if 

 necessary). Before cementing see that the layer of jelly is not 

 too thick. If too thick press some out and scrape away ; then 

 cool. 



Dammar Lac. — Dissolve in equal parts of benzene and oil 

 of turpentine. It does not render preparations as translucent 

 as Canada balsam. 



Fixing Blood 



As we have already stated, for practical purposes alcohol 

 is absolutely satisfactory. The following solutions have been 

 used, and may prove useful occasionally : — 



1. Os7nic acid. — Osmic acid, I'o; sodium chloride, o'6 ; 

 distilled water, loo'o. 



A neat and practical method of using this is to moisten a 

 camel's hair brush with the solution, then to touch the blood 

 drop, and to immediately spread the blood out on the slide 

 with the brush. Wash the brush, after use, in alcohol 

 (Kornilowitch). 



2. Chloroform. — Instead of heat in staining with Ehrlich's 

 triacid. Fix for five minutes in chloroform (neutral to litmus 

 paper). Stain for five minutes or more after fixing (.Tosue). 



3. Strong Flemming. Especially for nuclear structures 

 of parasites. 



4. Heat.^Hea.t up from one hundred to one hundred and 

 ten degrees C. in a hot oven, and then, when this temperature 

 is reached, allow to cool again in the oven. 



5. Osmic acid, two per cent., glacial acetic acid, equal 

 parts. Expose to the vapour. For delicate work indispensable.^ 



Staining Solutions for Blood, etc. 



1. Romanowsky stain (p. 10). 



2. Haematin (p. 50). — If the solution has become reddish 

 on keeping neutralize with a little ammonia. 



3. Eosin and Methylene Blue (consecutively).- — (a) Stain 

 for one to five minutes in a one-half per cent, solution of eosin 

 in sixty per cent, alcohol, wash, dry with blotting paper, and 

 stain (b) in a one per cent, solution of methylene blue for 

 thirty seconds to one minute. 



This is a useful and simple method for studying the acido,- 

 phil and basophil reactions of granules. 



