1899] MICROSCOPICAL JOURNAL. 217 



does not require dissolving out. It possesses the rare 

 quality of becomming as clear as glass, and quite invisi- 

 ble in the finished slide. First dehydrate on a slip by 

 running slightly-diluted absolute alcohol over the section, 

 and drawing off at one corner of the slide. It is prefer- 

 able, and, in case of serial sections, absolutely necessary, 

 to lay a thin cover-glass over the preparation, and allow 

 the alcohol to run between by capillary attraction. The 

 dehydration need not be very thoroughly carried out if 

 the cleaning is done with carbolic acid, which I strongly 

 recommend. The white crystallized acid must be used, 

 and, if manipulated in the following manner, no disagree- 

 able effects will result. Never allow it to touch the skin 

 — it burns badly ; and, above all, do not leave it about, 

 but keep it under lock and key. Take a common fiat 

 spirit bottle, nearly fill it with hot water, and, after cork- 

 ing tightly, lay it on its side. 



On this place the slide, with the covered section, and 

 plenty of the strong alcohol between the glasses. Strew 

 a few crystals of carbolic on, say, the left edge of the 

 cover ; they will instantly melt, and by the application of 

 a bit of blotting-paper to the opposite edge, the oily 

 liquid may be drawn under. The milky-white celloidin 

 rapidly becomes beautifully transparent, and when all 

 trace of cloudiness has disappeared, the cover may be re- 

 moved, and the now stiffened section transferred to a 

 covered pot of xylol. Use the xylol freely to get rid of 

 the carbolic, for I have known it to alter the color of the 

 stain to a warm brown if not removed. If the clearing- 

 is carried out without using a cover-glass, the section 

 wraps and twists badly. It occasionally happens that 

 the sections stick to the slip or cover. This risk is mini- 

 mized by keeping the film moving slightly, but with or- 

 dinary care there is not much risk of breakage from this 

 cause. Various oils may be used for clearing ; oil of 

 cedar-wood, for example. This is very slow in its action, 



