186 . Modern Microscopy 



5., In all cases the hardening process must be completed 

 in spirit. 



6. Label the' bottles, stating the contents, the hardening 

 fluid used, and when changed. Strict attention to 

 these details is necessary for successful histological 

 preparations, for if the hardening is neglected good 

 sections cannot be made. 



LESSON IL 



EMBEDDING TISSUES AND SECTION- 

 CUTTING. 



To Cut Sections with a Razor by Hand. — Take the 

 tissue between the thumb and forefinger of the left hand. 

 Hold the finger horizontally, so that its upper surface may 

 form a rest for the razor to slide on. Take the razor, hold 

 it firmly in the hand, keep the handle in a line with 

 the blade, and draw it through the tissue from heel to tip 

 towards yourself. While cutting, keep the razor well wetted 

 with dilute methylated spirit, and as the sections are cut 

 place them in a saucer of dilute methylated spirit. 



Embedding in Paraffin Wax and Lard. — Melt together 

 by the aid of gentle heat four parts of solid paraffin and 

 one part of lard. A quantity of this may be made and 

 kept ready for use at anytime. Melt the paraffin mass over 

 a water- bath. Take the specimen and dry it between the 

 folds of a cloth to remove the spirit, so that the paraffin 

 may adhere to its surfaces, place it in a pill-box in the 

 desired position, and pour in enough melted paraffin to 

 cover it, then set aside to cool. When quite cold, break 

 away the pill-box and cut sections from the embedded 

 mass with a sharp razor. When a number of specimens 

 are embedded, and it is desired to keep them for some 

 time, they should be preserved in a jar of methylated 

 spirit. 



