mVERTEBRATA, CRYPTOGAMIA, MICEOSCOPY, ETC, 693 



Carbolic Acid for Mounting.* — Mr. F. Barnard, of Kew, Victoria, 

 writes tliat some years ago he mentioned the use of carbolic acid (the 

 best crystallized with just sufficient water to keep it fluid) in mount- 

 ing microscoi)ical objects, and is led to believe that the subject is com- 

 paratively unknown in England, though in use in Victoria more than 

 ten years, and to such an extent that turpentine is seldom used in 

 many studios. The first specimen he saw it tried upon was the head 

 and jaws of a spider mounted by Mr. Ralph, the President of the 

 Microscopical Society of Victoria, which led Mr. Barnard to try it in 

 various ways to render objects transparent, and now he seldom uses 

 anything else. Whether it is animal or vegetable tissue the eflect 

 will be the same, the acid will in a very short time render the object 

 transparent, and the Canada balsam will when applied run in as 

 readily after it as turpentine. 



In the case of such an object as a palate of a mollusc, wash it well 

 in water and remove it to a bottle of the acid for a few hours, or if it 

 is desired to mount it at once, place it after washing on a glass slip 

 in proper position for mounting and drop one or two drojjs of the 

 acid on it. At first it will look thick and cloudy ; warm the slide 

 over the spirit lamp, let it cool, and drain oJBf the acid ; if not 

 perfectly clear when cold, apply some fresh acid and warm again ; 

 place on a cover if not previously done, and apply the balsam, by 

 means of a little heat it will run under. With polyzoa the easiest 

 plan is to jilace them in a little hot water which softens them, tlien 

 lay them out on a glass slip ; place another on it which is of suflicient 

 weight to keep them in position while they dry, then drop them into 

 a bottle of carbolic acid and soak for a time ; twenty-four hours will 

 render any polyzoa transparent without rendering them brittle, and 

 the author says he has mounted specimens perfectly clear and trans- 

 parent in ten minutes from the time they w^ere alive in the zoophyte 

 trough, ti'eating them as above recommended for palates. For 

 gizzards and parts of insects he also considers that nothing cornea 

 near it. 



One great advantage carbolic acid has over turpentine is that it 

 never renders specimens brittle. They can be pulled about as readily 

 as when frcsli. Should there over be any clouding, it arises from the 

 moisture of the object, not from the carbolic acid, but from want of 

 it. It is comparatively inexpensive, far less unpleasant in smell, and 

 not so sticky and dirty in use as turpentine. It is not necessary to 

 let the object dry, which invariably alters the shape more or less ; 

 still, should it be dry it is not any time becoming transparent com- 

 pared with the old process of soaking in turpentine. We all know 

 how difficult it is to render- Foraminifcra transparent and free from 

 air ready for mounting in balsam. One trial of carbolic acid will 

 convince the most sceptical of the advantages it has over turpentine, 

 benzine, &c. The only drawback to its use is that it often renders 

 some vegetable tissues too transi)arcnt. 



Double-staining of Vegetable Tissues.!— Ill this paper the writer 

 (who only givts an initiiil) says tliut, having used a number of dyes in 

 ♦ 'Sci.-Go.ssi|>," 1880, ]\ I'M. + ' Ain. M Mii-r. J,.nrn.,' i. (1880) p. 81. 



