144 CHAPTER X. 



can be removed in the cold if desired by putting the slide into 

 toluol, xylol, or the like. But the slide must, in any case, 

 be very thoroughly treated with alcohol after removal of the 

 paraffin, in order to get rid of the glycerin, which will cause 

 cloudiness if not perfectly removed. 



The function of the glycerin is merely to keep the layer 

 of albumen moist. 



Miss A. M. CLAYPOLE has written a paper complaining that the method 

 is uncertain, because too much heat may injure the tissues, and if too little 

 be applied the albumen will not coagulate. This is a misapprehension. 

 No heat whatever is required to coagulate the albumen ; the alcohol will do 

 that sufficiently. 



This method allows of the staining of sections on the slide 

 with perfect safety, both with alcoholic and aqueous stains, 

 provided they be not alkaline. 



This method can be combined with the water process for 

 flattening out sections (last ), as described by HKNNEGUY 

 (Journ. de I'Anat. et de la Physiol., 1891, p. 398). A drop 

 of water is spread by means of a glass rod on a slide pre- 

 pared with white -of-egg mixture, the sections are arranged 

 on it, the whole is warmed (not to the melting-point of the 

 paraffin) until the sections flatten out ; the water is then 

 evaporated off at a temperature of about 40 C., and as soon 

 as it has sufficiently disappeared, which at thnt temperature 

 will be in about ten minutes, the paraffin is melted, and the 

 slide further treated as above described. 



See also the description of this method given by OHLMACHE-E (Journ. 

 Amer. Med. Ass., April, 1893), who has independently worked out the 

 same process. 



The so-oalled " Japanese " method, attributed to IKEDA by REIXKE 

 (Zeit.f. wiss. Mik., xii, 1895, p. 21) is merely that of Henneguy. 



According to my experience the albumen method is abso- 

 lutely safe. It has the defect that certain plasma stains 

 (not chromatin stains) colour the albumen very strongly and 

 cannot be removed from it. 



It sometimes happens that the mixture after it has stood 

 for some time becomes turbid, a change which has been 

 attributed to the development of a microbe. I know of no 

 means of preventing the mixture from going bad in this way, 

 though I have found that it keeps better when freely 

 exposed to the sun. It has been stated (VOSSELER, Zeit. f. 



