SERIAL SECTION MOUNTING. 143 



the material has been properly imbedded. Sections stick 

 so fast by this method that they will stand staining on the 

 slide ; they will stand watery or other fluids for weeks, so 

 long as they are not alkaline, as these may cause them to 

 become detached. When successfully performed it is quite 

 safe, provided that the sections are of a suitable nature. 

 They must be such as to afford a sufficient continuous sur- 

 face, everywhere in contact with the slide. Sections of 

 parenchymatous organs stick well ; sections of thin- walled 

 tubular organs stick badly, often so badly that the method 

 is really not safe for them at all. Sections of chitinous 

 organs are very unsafe. The larger and thinner sections 

 are, the better do they stick, and vi<->' rn-sd. Sections from 

 material that has been fixed in chromic or osmic mixtures 

 are said to adhere less well than sections from alcohol or 

 sublimate material ; 1 find, however, that mine adhere per- 

 fectly well if otherwise suitable. The method has the dis- 

 advantage of being lengthy. And Mayer states that if it is 

 employed with stained material, the heat and drying may 

 attack some kinds of stains. 



183. MAYER'S Albumen (Mitth. Zool. Stat. Ntapel, iv, 1883; 

 Journ. Roy. J/iV. Soc. [N.S.], iv, 1884, p. 317; Littnint. 

 Munafwlir. f. An at., 1887, Heft 2; Jnrn. Rot/. Mic. Soc., 

 1888, p. 160. White of egg, 50 c.c. ; glycerin, 50 c.c. ; sali- 

 cylate of soda, 1 grm. Shake them Avell together, and filter 

 into a clean bottle. The filtering may take days or a week, 

 but the preparation does not spoil meanwhile. 



I find it convenient to beat up the egg with a little water 

 before adding the glycerin and filtering, the salicylate 

 being dissolved in the water in the first instance. 



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

 with a fine brush and well rubbed in with the finger. The 

 sections are laid on it and pressed down lightly with a brush. 

 The slide is then warmed for some minutes on a water-bath, 

 and the paraffin removed with a solvent. 



It is not necessary to use a water-bath for warming the 

 slide. I prefer to warm for an instant over a flame until 

 the paraffin melts ; it is then instantly removed by means of 

 xylol, tuluol, or the like. 



It is not necessary to warm the slide at all ; the paraffin 



