Ch. XI] PREPARATIONS BY THE PARAFEIN METHOD 381 



sections or work in a warmer place. If the sections crumple, make 

 thicker sections or work in a cooler room. Of course one can reimbed 

 in a more suitable hardness of paraffin. 



In the season when steam radiators are used one can get almost 

 any desired temperature by sectioning nearer or farther from the 

 radiator. 



In the winter it is a good plan to warm the microtome and section 

 knife before sectioning. This can be very easily done by putting 

 a cloth over the radiator and the microtome something like a tent. 



§ 616. Electrification of 

 the paraffin ribbons. — 



Some days there is such ~° ( * lT ~~zr~~r-mi.. 11- 



an accumulation of static 



electricity in cutting the 

 •Li .. .i • Fig. 22?. Fine Forceps for Handling Cover- 



nbbons that they jump glasses, Ribbon Sections, etc. 



toward anything brought 



near them. This is very annoying and liable to be so destructive to 



many of the sections that serial work cannot be done with safety. 



Many devices have been tried to overcome this difficulty, like burn- 

 ing a gas jet near the microtome, boiling water near the apparatus, 

 etc., but the safest way is to wait for more favorable conditions. 



To overcome this electrification, Dixon (Jour. Roy. Micr. Soc, 

 1904, p. 590) recommends fastening a 5-milligram tube of radium 

 bromide on the knife near where the sectioning is done. The radium 

 ionizes the air and renders it a good conductor, and then the static elec- 

 tricity cannot accumulate. I have not been able to try this method. 



§ 617. Storing paraffin ribbons. — The most convenient method for 

 caring for the ribbons as they are cut is to place them on a tray 

 (fig. 206-207) lined with a sheet of white paper. It is important to 

 write on the paper full data, giving the name of the tissue, the thick- 

 ness of the sections, the date, etc. It is well also to number the rib- 

 bons and to indicate clearly the position of the first section or the 

 beginning of the ribbon. 



Ribbons of sections on a tray should be covered by another tray 

 if one wishes to carry them to another room. The slightest gust of 

 air sends them flying. 



