APPENDIX 225 



Make a small paper trough, considerably larger than the 

 object to be imbedded; fill it with the melted paraffin, and 

 drop the saturated object into it in the exact position de- 

 sired for cutting the sections. When this is done cool the 

 paraffiin as quickly as posible by putting it in a basin of 

 cold water, being careful to keep the water away from the 

 paraffin until it is hard enough to prevent injury. When 

 it is thoroughly hardened, the paper may be removed and 

 the object is ready for cutting mto sections. It has been 

 suggested that glass tray salt cellars will accomplish the 

 work of the paper trough. 



6. Sectioning : The paraffin block m.ay be fixed on the 

 microtome by the method most convenient, and the sections 

 cut of the thickness desired. The particular method of 

 manipulating the microtome depends upon the structure of 

 the instrument. 



Mounting : Prepare a glass slide as follows : The slide 

 should be free from flaws, and should be ground at the 

 edges. See that it is thoroughly dry, and has a temperature 

 of about 60° C. Spread on the center of it a thin layer of 

 cement, or a diluted alcoholic solution of shell-lac, and allow 

 the alcohol to evaporate almost to dryness. Next spread a 

 bit of oil of cloves or turpentine on the slide, and place the 

 section on the moist slide. Allow the slide to remain for a 

 while in a warm place free from dust, in an oven if con- 

 venient, until the section is thoroughly cemented to tht 

 slide. Now put the slide in turpentine, or put turpentine 

 on the slide and allow it to remain until all the paraffin is 

 dissolved out of the tissue. 



When this is done the slide should be taken out of the 

 turpentine, a drop or two of balsam let fall on it, the size 



STU. IN ZOOL. — IS 



