Corrosive sublimate, saturated solution ..cubic centimeters 100 



Chromic acid of 1 per cent 50 



Kleinenberg ' s solution : 



Picric acid, saturated solution " 100 



Concentrated sulphuric acid 2 



Filter and add three times the volume of distilled 

 water . 



Flemming's solution: 



Chromic acid of 1 per cent 25 



Osmic acid of 1 per cent " 10 



Acetic acid (glacial) " " 5 



Distilled water " " 60 



Perenyi's solution: 



Nitric acid of 10 per cent 40 



Chromic acid of 1/2 per cent 30 



Alcohol of 90 per cent " " 30 



Muller's solution: 



Potassium bichromate grams 2 



Sodium sulphate 1 



Distilled water cubic centimeters 100 



Formalin solution (standard) : 



Commercial formalin 40 per cent 10 



Water " " 90 



Methods of Preparation and Preservation 



Protozoa 



Protozoa are so small for the most part as to be invisible 

 to the unaided eye, and their preparation therefore comes within 

 the field of the microscopist, for which reason only the larger 

 species will be mentioned here. Certain Gregarinas which occur 

 as parasites in the intestinal nucleus of Salpa maxima-africana 

 are best preserved with Kleinenberg ' s solution, where they may 

 remain for about an hour before they are transferred to weak 

 alcohol. 



Radiolaria 



Thalassicolla is well fixed in chromic acid of 1/2 of 1 

 per cent, where it may remain about an hour and then be trans- 

 ferred gradually to alcohol of 70 per cent. 



Aulacanthidae and Acanthometrae are placed directly in 

 50 per cent alcohol, and after a few hours are transferred to 

 that of 70 per cent. Good preparations have also been made by 

 dropping a few drops of 1 per cent osmic acid into the sea water 

 containing the animals and then transferring them to alcohol 

 after washing them in fresh water. Excellent microscopic pre- 

 parations of some of these species of minute pelagic organisms 



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