1886.] 



MICROSCOPICAL JOURNAL. 



not entirely those of to-day, but 

 they are inherited from past genera- 

 tions. Hence it is that few Hves 

 are truly great and noble, even in 

 the search for truth, but some are 

 greater and more noble than they 

 seem, for after all it is the hidden 

 motive anid desire that moulds the 

 character. 



So, when a great man passes out 

 of the world, it is hard to fill his 

 place ; yet he leaves behind an exam- 

 ple of a life well spent, which will be 

 an influence to be felt long afterward. 

 Such a man was Dr. Carpenter. His 

 death is a great loss to the world, but 

 it could not, in any case, have been 

 long delayed. He leaves behind a 

 legacy more to be prized than the 

 fame and wealth of kings, the memory 

 of a man who was truly great. 



A New Mounting" Medium of High 

 Refractive Index. 



Professor Hamilton L. Smith has 

 recently discovered a mounting me- 

 dium which he regards as superior 

 to any hitherto described. It is 

 even superior to the preparations 

 described in these columns in Sep- 

 tember of last year. These con- 

 sisted of stannous chloride in 

 glycerin jelly, giving a refractive in- 

 dex of 1.7, and of realgar in arsenic 

 bromide, with a refractive index of 

 2.4. The new medium, which has 

 a refractive index considera]:)ly above 

 that of the stannous chloride me- 

 dium, is prepared in the following 

 manner : — 



Dissolve li ounces of antimony 

 bromide in two fluid drachms of a 

 fifty per cent, solution of boro-glycer- 

 ide. This, when cold, makes a very 

 viscid medium, like old stiff' balsam, 

 of a dark, sherry wine color. Mounts 

 made with it in the extremely thin 

 film required are as colorless as with 

 old balsam, and when laid upon 

 white paper the color of the medium 

 is clearly perceptible if it has not 

 been injuretl by overheating — cer- 

 tainly less than most mounts in sty- 

 rax. 



It is used precisely like Canada 

 balsam. It works easily at a moder- 

 ate heat, and boils very readily. The 

 heat must be continued until the 

 boiling is nearly over, but care must 

 be observed not to overheat, as the 

 glycerin is liable to burn. When 

 entirely cooled the cover will be 

 firmly attached, as with balsam, and 

 the slide ma}' be cleaned with moist 

 tissue paper, without fear of disturb- 

 ing the cover. 



A finishing ring may now be ap- 

 plied, but Prof. Smith advises that a 

 bit of paraffin should be placed on 

 the slide, melted, and caused to ffow 

 around the mount, by tilting the 

 preparation. A vigorous rubbing 

 with a cloth will remove all excess of 

 paraffin, leaving a sloping or bev- 

 elled ring around the mount. This 

 operation has preserved mounts for 

 two months already, with no indica- 

 tion of change. Any finishing ce- 

 ment may then be applied. 



The medium is only slightly de- 

 liquescent, but is decomposed by 

 water and injured by contact with 

 immersion fluids, hence some pro- 

 tection is necessary. 



We now quote from Prof. Smith's 

 letter as follows :^ 



' The boro-glj'ceride which I have 

 used was prepared for me by Mr. 

 C. F. Booth, of Tarrant & Co., 

 manufacturing chemists. New York. 

 This substance is a hard, brittle, and 

 glassy compound of glycerin and 

 boracic acid, and will no doubt serve 

 an excellent purpose as a mounting 

 material from its antiseptic proper- 

 ties. I use a 50 per cent, solution of 

 this in glycerin. 



' I wish to say here that recently, 

 in looking over some of my earliest 

 mounts in the chloride of tin and 

 glycerin medium that I had thrown 

 aside because of leakage (as this 

 material, before I used gelatin, al- 

 ways remained more or less soft, 

 and so made it difficult to clean off' 

 the cover before ringing) , I was sur- 

 prised to find that not only had the 

 leakage stopped but that the drop 



