rock, in incrustations of calcareous algae, and among colonies 

 of serpulas and of madrepores. Such must be allowed to remain 

 in the solution from six to twelve hours. It is not necessary 

 to use a fine quality of the drug. 



Cocaine . — A solution of cocaine is made by dissolving 

 2 grams of the powder in 100 cubic centimeters of 50 per cent 

 alcohol. This is a most excellent narcotizing medium, but its 

 high cost prevents its extensive use. It is the best reagent 

 thus far discovered for the treatment of gastropods. A few 

 drops are carefully distributed over the surface of the water 

 containing the animals, and the operation is repeated until 

 the animals cease to respond to any stimulus. 



Other reagents that are used occasionally are chloro - 

 form , ether, and tincture of iodine . 



Mixtures frequently used. 



Alcohol of 70 per cent and chromic acid of 1 per cent in equal 

 parts. 



Alcohol of 50 per cent cubic centimeters 



Hydrochloric acid (concentrated) 



Alcohol of 35 per cent or of 70 per cent 



Alcoholic tincture of iodine 



Alcoholized sea water: 



Sea water 



Absolute alcohol 



Chrom-acetic mixture No. 1: 



Chromic acid of 1 per cent 



Concentrated acetic acid 



Chrom-acetic mixture No. 2: 



Chromic acid of 1 per cent 



Concentrated acetic acid 



Chrom-osmic mixture: 



Chromic acid of 1 per cent 



Osmic acid of 1 per cent ^.. 



Chrom-picric mixture: 



Chromic acid of 1 per cent 



Kleinenberg ' s solution 



Sulphate of copper, solution of 10 per 



cent strength 



Corrosive sublimate, saturated solution 

 Potassium bichromate, 5 per cent solution 



Osmic acid, 1 per cent solution 



Corrosive sublimate, saturated solution 

 Acetic acid, concentrated 



100 

 5 



100 

 2. 



100 

 5 



100 

 5 



10 

 100 



100 

 2 



50 

 50 



100 

 10 



100 

 2 



100 

 50 



18 - 



