(C) SOME KILLING, FIXING, PRESERVING REAGENTS 



AND THEIR USES 



ACIDS 



Acetic 

 1) 

 2) 



3) 

 4) 



Chromic 

 1) 



Permeates and hardens tissues instantly. 

 Rapidly kills contractile forms (tissues soften 

 if left in too long) . 



Objects remain relatively transparent in it. 

 Used with chromic acid it is effective for 

 killing and hardening non-contractile forms. 



Next to alcohol, in an aqueous solution, it is 

 the most useful reagent for killing and harden- 

 ing soft, gelatinous forms. 



Caution - Objects become fragile and too deeply 

 tinged if left in it longer than necessary. 

 After treatment, wash animals in fresh water to 

 avoid a precipitate when they are later placed 

 in alcohol. 



When mixing chromic with osmic, acetic, picric 

 or corrosive sublimate, use FRESHWATER. 

 Solutions do not keep long. 



Solutions that have turned green are not fit to 

 use. (Solutions may be used if they are not too 

 dilute when mixed with the water containing the 

 specimen) . 



Hydrochloric - USE RARE - Mixed with 50% alcohol, 



2) 

 3) 



4) 



5) 

 6) 



Lactic 

 1) 



Osmic - 

 1) 



2) 

 3) 



A solution of 1-1000 seawater effective for larval 

 and small gelatinous forms. 



USE RARE TODAY. 



Hardens gelatinous forms and preserves transparency 



well, but its action is too great. 



Caution - Animals should remain in it only until 



they are light brown color. 



It is used in 



a) Chrom-osmic mixture. 



b) Potassium bichromate-osmic acid. 



c) Flemming's solution. 



- 55 - 



