MOUNTING AND PREPARATION OP OBJECTS. 71 



roughly in air. When dry it is mounted in Balsam 

 in the usual manner. 



Sections of hardened tissue are treated in the same 

 manner, and the bacillus is shown by this method 

 equally well in sections hardened in spirit and chromic 

 acid. 



We consider this an excellent modification of the 

 older methods, and although the photograph of the 

 bacillus anthracis in the frontispiece, was prepared 

 by Elrichs original method, the results obtained with 

 the tubercle bacillus, by the modified plan, were 

 superior. 



Bone and all substances containing an organic 

 basis impregnated with earthy salts may be softened 

 by dissolving out the latter by prolonged maceration 

 in dilute acid, their consistency after this treatment 

 will allow of their being cut in the microtome with- 

 out freezing, if embedded in parafin and wax. 



Rocks, fossils, and bone when not softened, re- 

 quire entirely different treatment and considerable 

 skill before they arrive at a condition suitable for 

 microscopic investigation. A very slight sketch of 

 the plan adopted is here given to enable those who 

 do not possess a lapidary's workshop to investigate 

 these substances under low powers. 



A rough slice is cut from the substance with a 

 small saw or by chipping ; one side is fastened with 

 balsam about an inch from the extremity of a board; 

 twelve inches long, two inches wide, and half an 

 inch thick. When the balsam has hardened, the 



