ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



839 



transferred to the copper and bichromate solution, wherein it becomes 

 stained Wack. Sections stained in this way are extremely valuable for 

 photomicrography. The sections thus stained may be mounted in 

 acetate of potash, glycerin, or in balsam. 



C5) Mounting', including- Slides, Preservative Fluids, &c. 

 Method for fixing Serial Sections to the Slide.*— Dr. (Jallemaerts 

 recommends Drash's method fur tixing sections to the slide. It is per- 

 formed as follows : — 



(1) Make a saturated solution of gun-cotton in acetone, and then add 

 enough absolute alcohol to the solution to make a very thin fluid 



(2) Cover the slide with a thin layer of the liquid. 



(3) Arrange the sections, then moisten the slide with a brush dipped 

 in absolute alcohol in order to dissolve the coat. 



(4) Mop up the sections with blotting-paper by pressing several folds 

 down on the slide with the finger. 



(5) Warm the slide until the paraflfiu melts. 



(6) When cool dissolve the paraffin in xylol and mount in balsam. 



(7) If the preparations are not stained, after the xylol wash with 

 alcohol ; then place them in the stain. When stained, wash in water, 

 and then pass through alcohol and xylol to balsam. 



Apparatus for fixing down Series of Sections.! — Dr. I- Dionisio 

 has devised an apparatus for facilitating the manipulation of series of 

 sections. The idea of the apparatus consists in keeping the sections on 

 the slide during the manipulation by means of a fine wire sieve, the 

 meshes of which are jjroportionate to the size of the preparations. 



The apparatus consists of a circular flat ring of metal a, upon which 



Fig. 113. 



lies the oblong frame b. From the long sides of b two pieces d d extend, 

 and end in rounded extremities, through which pass two screws cc. 

 These connect the two movable parts, and when the screw-head e is 

 turned down, these two parts are firmly fixed together. 



Sections fixed up in this way can be treated thoughout tlie various 

 stages of staining, washing, dehydration, &c., but it is obvious that the 

 instrument cannot be employed with reagents which act upon it (acids, 

 &c.) ; hence its use would appear to be somewhat limited. 



* Bull. Soc. Belg. de Micr., xv. (1889) pp. 56-7. 



t MT. Embryol. Instit. Uuiv. Wien, 1888, pp. SO-4 (1 fio-.). 



