ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 739 



they can easily be fastened in place again. I also find this a quicker 

 method of mounting, it not being necessary to take so much pains to 

 avoid running in. If the cover-glass is broken by accident, it is, of 

 course, easily replaced, which is another decided advantage. But the 

 greatest gain is in the fact that the object can be examined uncovered. 

 In working with metallic crystals and the binocular I have often ex- 

 perienced great difficulty from the interference caused by the cover, 

 and find it a great advantage to remove it altogether when studying. 

 Such are the advantages of the new method. If it has any disadvan- 

 tages I have failed to find them, after a year's trial." 



Glycerine Mounting.* — Eeferring to Prof. Hillhouse's method, 

 ante, p. 599, Mr. J. W. Neville, from practical experience, suggests 

 the sealing of the cover-glass with pale copal varnish instead of dilute 

 balsam. It can be obtained of as light a colour, is much tougher, and 

 not likely to get so brittle as that medium. He has preparations that 

 have been put up in this way for seven years or more, and several of 

 his friends have used it as long a time, preferring it to glycerine jelly, 

 as it does not show such a disposition to leak. Practical microscopists 

 will be glad to learn that after this space of time the objects show no 

 signs of deterioration, but rather wear an improved appearance. 



Mr. G. E. Davis also writes : f — " Much has been said against 

 glycerine mounts and their leaky propensities after a lapse of time. 

 We have lately seen some glycerine preparations put up ten years ago, 

 and they are to-day as tight as when first mounted. The only varnish 

 used for cell and cement was white zinc varnish. We have many 

 glycerine mounts in our cabinet, and have come to the conclusion long 

 ago that if every care were taken to clean away the superfluous 

 glycerine there would be no more complaints of leakage. No cement 

 will adhere where there is even the slightest film of glycerine." 



Dr. H. T. Whittell | has tried, with limited success, all the 

 plans and cements that he has seen recommended for mounting 

 objects lying imder the cover-glass floating in a drop of water or 

 glycerine, with some of the same fluid outside the cover-glass so as 

 to preserve the object in the exact condition in which it has been 

 found, but has obtained much more satisfactory results by the 

 following simple plan : — 



As much glycerine as possible is first removed from the slide by 

 the usual plan of wiping, and absorbing with bibulous paper round the 

 edges of the cover. A little gold-size — that sold to artists is best — is 

 rubbed up with a little whiting that has been previously well dried in 

 an oven, and this is poured into a bottle for use. Some of the whiting 

 settles to the bottom, but a quantity is held in suspension, and a larger 

 proportion can always be obtained by shaking up the bottle. By 

 means of a fine brush a little of this chalk cement is passed along the 

 edges, and just outside the cover-glass, taking care to fill up the angle 

 between the slide and cover. To prevent moving the preparation, it 

 is better in this stage to imitate what the artists call " stippling," that 



* Midi. Natural., vi. (1883) p. 190. 



t Micr. News, iii. (1883) p. 238. 



X Journ. Quek. Micr. Club, i, (1888) pp. 191-3. 



