114 SERIAL SECTION MOUNTING 



arable (1 or 2 drops of mucilage to a glass of water) ; Apathy 

 (Microtechnik, p. 126) adds 1 per cent, of Mayer's albumen (§ 209) ; and 

 Henneguy (Legons stir la Cellule, 1896, p. 62) takes a 1 : 5,000 solution 

 of gelatin, with a trace of bichromate of potash, added just before 

 using, and dries the slides exposed to light. Similarly, Bubchardt 

 {Jena Zeit., xxxiv, 1900, p. 719). 



Some workers have used alcohol (50 or 70 per cent.) instead of water ; 

 but this we believe to be now generally abandoned. 



This is the most elegant method of any, as there is nothing 

 on the shde except the sections that can stain, or appear as dirt 

 in the mount. Tissues do not suffer from the drying, provided 

 the material has been properly imbedded. Sections stick so 

 fast by this method that they will stand watery or other fluids 

 for weeks, so long as they are not alkaline. When successfully 

 performed it is quite safe, provided that the sections are of a 

 suitable nature. They must be such as to afford a sufficiently 

 continuous surface, everywhere in contact with the slide. Sections 

 of parenchymatous organs stick well ; sections of thin-walled 

 tubular organs stick badly. Sections of chitinous organs are very 

 unsafe. The larger and thinner sections are, the better do they 

 stick, and vice versa. Sections from chromic or osmic material 

 adhere less well than sections from alcohol or sublimate material. 



By taking a staining solution instead of pure water for expanding, 

 the sections can be got to stain at the same time, and so be brought into 

 balsam without passing through alcohol ; see Mayer, Mitth. Zool. Stat. 

 Neapel, xii, 1896, p. 320 ; Schmorl, Path.-hist Untersuchungsmethoden, 

 1897, p. 38 ; Smith, Journ. Anat. Phys., xxxiv, 1899, p. 151. 



209. Mayer's Albumen {Mitth. Zool. Stat. Neapel, iv, 1883 ; 

 Internal. Monatschr. f. Anat., iv, 1887, p. 42). White of egg, 

 50 c.c. ; glycerin, 50 c.c. ; salicylate of soda, 1 grm. Shake 

 them well together, and filter into a clean bottle. The filtering 

 may take days or a week, but the preparation does not spoil 

 meanwhile. 



Francotte shakes up the albumen with a few drops of acetic 

 acid before adding the other ingredients, and finds the filtering 

 greatly quickened. 



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

 brush and well rubbed in with the finger (Lee preferred a small 

 rubber " squeegee "). The sections are laid on it and pressed 

 down lightly with a brush (if they will bear it). The slide may 

 then be warmed for some minutes on a water-bath, and the 

 paraffin removed with a solvent. 



It is 7iot necessary to warn^ the slide at all ; the paraffin can be 

 removed in the cold if desired by putting the slide into toluol, 

 xylol, or the like. But the slide 7nust, in any case, be treated with 

 alcohol after removal of the paraffin, in order to get rid of the 

 glycerin, which will cause cloudiness if not perfectly removed. 



