72 Modern Microscopy. 



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 2. 



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, and 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 any time. 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. 



To infiltrate a Tissue with Paraffin. Place the speci- 

 men in absolute alcohol or chloroform for an hour or two, 

 then transfer to a bath of melted paraffin of 110 F. 

 (melting-point), and keep it at this temperature for several 

 hours, so that the paraffin may penetrate to the middle of 



