744 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the object practically would be sealed hermetically in glass; the 

 contact of the media with the cement would be so slight as to be 

 hardly worth considering. Objects thus mounted would, it is claimed, 

 be as permanent as the glass itself. 



Finish for Slides.* — Dr. J. E. Hays recommends the following as 

 a handsome finish for slides. 



Take one of the packages of " gold or silver paints " put up by 

 Wells and Eichardson, of Burlington, Yt., and sold in connection 

 with their " diamond dyes," and add it to 1/2 oz. of the best dammar 

 varnish, warming the varnish so as to make the paint mix with it well, 

 and apply with a fine brush. The paint will settle to the bottom 

 upon standing, but by warming a little and shaking well it is diffused 

 again. This makes a very pretty finish, and adds strength to the 

 cover cement as well. 



Counting of Microscopic Objects for Botanical purposes.f — M. E. 

 C. Hansen recommends the application to botany of the method of 

 counting blood-corpuscles adopted by physiologists. The apparatus 

 devised by Hayem and Nachet is equally applicable to the counting of 

 yeast-cells, as well as in examinations of air, water and soil for 

 microbes. It is also useful for making pure cultures when it is neces- 

 sary to ascertain the number of micro-organisms in a given quantity 

 of liquid to determine the extent of the dilution required. In a 

 similar way Jorgensen determined the proportions of each substance 

 in a mixture of rye and wheat flour. 



Styrax and Balsam. — Prof. A. B. Aubert's | experience with 

 styrax has proved that in most cases it can be used instead of 

 Canada balsam — indeed, that it is superior to balsam, showing the finer 

 part of objects more clearly. He has entirely discarded balsam for 

 diatoms. Cartilage, when properly stained, shows very well, better in 

 his opinion than in glycerin-jelly. For histological objects generally, 

 he anticipates it will be a welcome addition to the present stock of 

 mounting media. Tooth, bone, and other sections would undoubtedly 

 show to better advantage in this medium than in balsam. 



Mr, C. V. Smith, the well-known mounter of botanical objects, to 

 whom he sent specimens of the gum, spoke very highly of it for 

 botanical mounts, and said that he never tried any medium which 

 showed aleurone-grains in section of castor-oil plant so satisfactorily. 

 It also shows the mycelia of fungi more clearly than most other 

 media. 



Objects mounted a year ago show no sign of deterioration, and 

 there is every reason to believe that it will prove an excellent medium 

 for permanent mounts, preferable to balsam, not only on account of 

 its highly refractive index but also because it seems somewhat less 

 brittle. When the solutions kept in capped bottles become thick by 

 evaporation, it is best to transfer them to a common bottle and add 

 the proper amount of solvent. This will cause a flocculent precipitate. 



* The Microscope, v. (1885) p. 112. 



t Zeitschr. f. Wiss. Mikr., i. (1884) pp. 191-210 (6 figs.). 



X Amer. Mon. Micr. Journ., vi. (1885) pp. 86-7. 



