3 1 8 PR A CTICAL MICROSCOP Y. 



oil of cloves, and is in every way cheaper, as one volume of 

 it absorbs eleven volumes of alcohol, or is eleven times 

 more efficient than oil of cloves. 



And now we must consider water, perhaps the most 

 useful solvent we have. A great many substances are 

 soluble in this fluid, and even those generally considered 

 insoluble are acted upon to such an extent as to interfere 

 with it for microscopical purposes. Air, or rather the 

 oxygen and nitrogen of the air, are soluble in water, and 

 cause the microscopist no little trouble. This has been 

 dealt with on page 304, and it may also be stated that 

 when water is to be evaporated on a slide for future 

 mounting, the water should be distilled, so that no 

 objectionable residue is left. 



RECIPES. 



CARBOLIC ACID (Fluid). 



Procure an ounce bottle of Calvert's pure crystallised carbolic acid, place it 

 in a jar of warm water to melt ; then add two drachms of methylated spirit, 

 mix, and preserve for use. 



If strong carbolic acid be spilled upon the hands, it must be immediately 

 wiped off with oil, not water. 



CARBOLIC ACID WATER. 

 Strong. 



Fluid carbolic acid I drachm. 



Distilled water 16 oz. 



Weak. 



Carbolic acid water (strong) i oz. 



Distilled water . . . . 9 oz. 



CHLORINATED SODA (solution}. 



Dry chloride of lime 2 oz. 



Soda crystals (washing soda) 3 oz. 



Water 2 pints. 



Mix the chloride of lime with half the water, and the soda in the other half, 

 mix the whole together, and allow to settle in a well-corked bottle. Pour off 

 the clear liquid for use, which must be kept in a well-corked bottle. 



