4 MICROSCOPICAL RESEARCH 



Oil of Bergamot is used as a clearing agent for all celloidinized sections on 

 account of it having no appreciable action on the celloidine. Celloidine is 

 dissolved when placed in contact with oil of cloves or cajeput. 



Oil of Cloves, being slower in its action than either of the above, is generally 

 used for clearing tissue in bulk, and for graduating delicate objects out of alcohol, 

 which would be contracted or destroyed by transferring them direct from alcohol 

 to the oil (Fig. A). 



Celloidine. 



Schering's celloidine chips are recommended for use; it is put up in one 

 ounce sealed boxes. Celloidine is soluble in a mixture of equal parts of absolute 

 alcohol and ether, and is used for "celloidinising" animal and vegetable tissues, when 

 it is required to bind or hold together any loose parts which we may desire to 

 examine in their natural positions. 



Celloidine does not "infiltrate" the tissues, but only surrounds and binds, or 

 holds them in position during the manipulative processes. 



Acidulated Alcohol. 



Hydrochloric acid, two drops (minims). 

 92 per cent, alcohol, one ounce. 



This solution is found useful in reducing the colour of overstained sections. 

 Sections stained with carmine or haematoxylin may require a stronger solution 

 for their reduction, or a prolonged soaking. Aniline-stained sections seldom 

 require the use of acid alcohol, alcohol free from acid will generally be found 

 sufficient for the purpose. Sections on which acid alcohol has been used must 

 in all cases be rinsed in alcohol free from acid before passing them on to the 

 next process. 



Bleaching Solution. 



Sections must never be bleached when it is desired to retain the cell-contents, 

 but only when it is necessary to cleanse the sections of resinous matter so as to 

 admit of better staining. After bleaching, the sections must in all cases be freed 

 from the chlorine by prolonged washing in water, or by reagents, before staining. 



