160 GENERAL BIOLOGY 



Methyl Green. A strong aqueous solution (1 per .cent) 

 with 1 per cent of acetic acid. An excellent stain for fresh 

 tissues. Stains the nucleus only, stains rapidly and does 

 not overstain. 



Methylene Blue. Pure methylene blue added to water to 

 make a light blue tint will stain parts of the living animals 

 contained in the water. Several hours are usually neces- 

 sary. Does not affect the animals, but the stain should 

 be pure for this purpose. 



Normal Salt Solution. Dissolve 7 g. of common salt in 

 1000 cc of water. This solution is used as a medium for 

 the examination of fresh tissues. The concentration ap- 

 proaches that of the lymph, and tissues and cells in it are 

 not distorted as they would be in water. 



Pasteur's Solution. 



Ammonium tartrate . 

 Potassium phosphate 

 Calcium phosphate . 

 Magnesium sulphate 

 Cane sugar 

 Water to make 



50 g. 



10 g. 



lg. 



1 g. 



750 g. 



5000 cc 



This solution is used as a culture medium for yeast, moulds 

 and bacteria. The Pasteur's solution without sugar is the 

 same wdth the sugar omitted. 



Worcester's Fluid. This fluid is a saturated solution of 

 corrosive sublimate (mercuric chloride) in 10 per cent 

 formalin. For small animals and small pieces of tissue kill 

 for fifteen minutes to an hour. Wash in water, preserve in 

 formalin or alcohol. Especially good for killing Paramecium 

 and Protozoa. If used hot Protozoa and hydra are killed 

 instantly. 



Zenker's Fluid. 



Corrosive sublimate (mercuric chloride) . , 5 g 



Potassium bichromate ... 2 o'e 



Water .'.".' l<X/cc 



Just before using add glacial acetic acid ... 5 cc 



