HARDENING AND FIXING KEAGENTS. 3 



For fixing nuclear figures the strongest Alcohol (Absolute) 

 should be used, and the pieces should be as small as possible. 



Throughout this book, per cent, of Alcohol is given by 

 weight ; when Methylated Spirit is used the gravities may be 

 slightly different. The following formulae are sufficiently near 

 for all practical purposes. 



Absolute Alcohol, about 98 per cent. Sp. gr. 0-797. 

 The commercial article. Alcohol Ethylicum B.P. 



Alcohol, 9O per cent. Sp. gr. 0-823. 



Absolute Alcohol, 14 vols. ; Distilled Water, 1 vol. : mix. 



The strongest commercial Methylated Spirit (64 o. p.) is 

 practically the same strength as 90 p. c. Alcohol, and being 

 duty free is much cheaper and answers every purpose. 



This, of course, only applies to Methylated Spirit free from 

 Mineral Naphtha. The ordinary , ' ' Eetailer ' s ' ' quality contains 

 Naphtha, and becomes turbid when mixed with water. 



Alcohol, 84 per cent. Sp. gr. 0-838. 

 This is Eectified Spirit B.P. (56 o. p.). 



Alcohol, 70 per cent. Sp. gr. 0-872. 



Absolute Alcohol, 3 vols. ; Distilled Water, 1 vol. 

 Eectified Spirit, 6 vols. ; Distilled Water, 1 vol. 

 Methylated Spirit, 4 vols. ; Distilled Water, 1 vol. 



Alcohol, 50 per cent. Sp. gr. 0-918. 



Absolute Alcohol, 5 vois. ; Distilled Water, 4 vols. 

 Eectified Spirit, 5 vols. ; Distilled Water, 3 vols. 

 Methylated Spirit, 5 vols. ; Distilled Water, 3J vols. 



(ii.) ALCOHOL AND ACETIC ACID. 



Absolute Alcohol, 75 c.c. ; Glacial Acetic Acid, 25 c.c. 

 This is an excellent fixing agent for nuclei. Tissues are 



