LABORATORY DIRECTIONS. 473 



Flemming's Solution. 



Osmic acid, 1 per cent, aqueous 



solution 10 parts. 



Chromic acid, 1 per cent, aque- 

 ous solution 25 parts. 



Glacial acetic acid, 1 per cent. 



aqueous solution 10 parts. 



Distilled water 55 parts. 



Fix for twenty-four hours or more and wash thor- 

 oughly in running water. 



Flemming's Strong Solution. 



Osmic acid, 2 per cent, aqueous 



solution 4 parts. 



Chromic acid, 1 per cent, aque- 

 ous solution 15 parts. 



Glacial acetic acid 1 part. 



This is a good fixing agent for nuclear structures 

 and therefore for mitosis. 



Corrosive Sublimate. 



Saturated solution in distilled water. Fix for 

 twenty-four hours or more and wash in running water. 

 After twenty-four hours, transfer to 70 per cent, 

 alcohol to which a few drops of iodin and potassium 

 iodid have been added. The iodin removes any 

 crystals of sublimate that may have formed. 



Picric Acid. 



Saturated aqueous solution. Fix for twenty-four 

 hours, or longer, after which wash in 70 per cent, 

 alcohol. 



Picrosulphuric Acid. 



Picric acid, saturated aqueous 



solution 100 parts. 



Sulphuric acid, concentrated... 1 part. 



Distilled water 200 parts. 



After-treatment same as for picric acid. 

 Nitric Acid. Aqueous solution, 3 to 10 per cent. 



