1881.] 



MICEOSCOPICAL JOIJKNAL. 



Two wide-mouthed bottles, each 

 of about two ounces capacity, are 

 procured. Corks are fitted to them 

 and the corks are connected by a 

 short piece of glass tubing which is 

 bent at each end, and passes down 

 through the corks, passing just 

 through one cork and far enough 

 through the other so as to almost 

 touch the bottom of the bottle when 

 the cork is inserted. A channel is 

 to be made in the side of the cork 

 carrying the long arm of the tube, and 

 one of the bottles is then filled about 

 three quarters full of filtered rain- 

 water, and in this the sections to be 

 bleached are placed. In the other 

 bottle a sufficient quantity of chlorate 

 of potash in crystals is placed to just 

 cover the bottom, and then a drachm 

 or so of strong hydrochloric acid is 

 poured upon them. The corks are 

 then placed in the bottles, being par- 

 ticular to put the cork carrying the 

 long arm of the tube in the bottle 

 containing the sections. The yellow 

 vapor of chlorine (or, rather, of eu- 

 chlorine), immediately begins to be 

 evolved and passes over through the 

 tube into the water containing the 

 sections. When the water becomes 

 saturated with chlorine, the excess 

 rises and escapes through the chan- 

 nel in the cork. It is Mr. Marsh's 

 practice to arrange the apparatus for 

 work at night and to set it out of doors 

 in a covered place, in order to avoid 

 annoyance from the escaping fumes 

 of chlorine. 



To wash the sections after bleach- 

 ing, a bottle is taken, similar to 

 the others, but having a small aperture 

 filed in the side at the shoulder. The 

 bleached sections are placed in the 

 bottle and covered with filtered water. 

 A small funnel is then fitted to the 

 cork, and the neck of the funnel is 

 continued to the bottom of the bottle 

 by a piece of fine rubber-tubing, the 

 tube being carried to the side of the 

 bottle opposite the aperture. A sheet 

 of filtering paper being placed in the 

 funnel, the bottle is placed beneath 

 a water tap and a gentle stream of 



water allowed to trickle into the fun- 

 nel continuously. A constant circu- 

 lation of water is thus maintained in 

 the bottle, the discharge being through 

 the orifice in the side. As in the 

 case of the bleaching the apparatus 

 is set to work at night, and in the 

 morning the sections will be found 

 to be thoroughly washed. 



The advantages claimed by Mr. 

 Marsh for this method are that the 

 sections are effectually bleached with- 

 out being subjected to the destructive 

 and disintegrating action of the chlor- 

 inated soda solution; neither will the 

 sections suft'er from the deposit upon 

 them of a scum of carbonate of lime, 

 as frequently happens in the use of 

 the ordinary bleaching fluids. The 

 apparatus is easily constructed and 

 the results are very satisfactory. 



A. L. Woodward. 



The Preparation and Mounting 

 of Microscopic Objects. 



IV. In the preceding articles upon 

 this subject, we have considered " Ce- 

 ments and Apparatus," "Dry Mount- 

 ing," and "Mounting in Fluid." There 

 is still another method of mounting 

 which is more generally employed 

 than any other, viz. : mounting in bal- 

 sam. There are several methods of 

 preparing balsam-mounts, and the 

 microscopist is governed in his selec- 

 tion by the character of the object. 

 A few hints upon this subject will be 

 found in the course of this article. 



Mounting in Balsam. The object 

 of mounting in Canada-balsam is to 

 render the objects clear and transpa- 

 rent. It can readily be understood 

 that by filling the pores of an object 

 with a highly refracting medium, that 

 object will become transparent, for 

 the same reason that a piece of paper 

 is rendered clearer when a drop of 

 oil is applied to it. To decide whether 

 an object should be mounted in bal- 

 sam or in some other medium, it 

 should be subjected to a preliminary 

 examination in water and in turpen- 

 tine, and if it looks better in the tur- 



