FLOGEI/S GUM METHOD. 177 



of soda, 1 gramme. Shake them well together, and filter 

 into a clean bottle. 



FOL (Lehrb., p. 134) takes whipped white of egg, filters it 

 through a Bunsen filter, and adds the glycerin and a little 

 camphor or carbolic acid. 



According to nay experience, carbolic acid is perfectly 

 efficient as a preservative, but is not to be recommended 

 because it precipitates a great deal of the albumen. 



A thin layer of the mixture is spread on a cold slide with a 

 fine brush and the sections laid on it, and warmed for some 

 minutes on a water-bath. As the paraffin in the sections 

 melts it carries the albumen away from them, and this is one 

 of the advantages of the method. The sections may be treated 

 with turpentine, alcohol, and aqueous or other stains without 

 any danger of their moving. 



The function of the glycerin is merely to keep the layer of 

 albumen moist. 



This method allows of the staining of sections on the slide 

 with anilin stains, which is seldom practicable with Schalli- 

 baum's method, as the collodion stains with most anilin stains, 

 and does not yield up the colour to alcohol. 



The slide should 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 re- 

 moved. 



According to my experience, this method is absolutely safe, 

 and is the one that should in general be preferred for staining 

 on the slide, more especially for staining with anilins by 

 Flemming's method. 



319. Flogel's Gum Method (Zool. Anz., 1883, p. 565). Make 

 a solution of one part gum arabic in twenty parts water, filter, 

 and add a little alcohol to prevent the formation of mould. 

 Slides are prepared by pouring the solution over them, and 

 draining. (It is important that the slides be so perfectly 

 clean as to be evenly wetted all over by the gum solution.) 

 Sections may now be cut and laid on the gum surface before 

 it has become dry, and floated into the proper position ; this 

 is the best plan for sections of y^- mm. thickness, and for 

 large sections. For thinner and small sections it is best to 

 take slides that have completely dried, arrange the sections 



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