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SCIENCE-GOSSIP. 



Mounting Delicate Micro-Organisms. — In 

 reply to the enquiry {ante page 21) on this subject, 

 the process for mounting Rotatoria, practised with 

 great success by Mr. Charles Rousselet, F.R.M.S., 

 and given in full in the "Journal of the Quekett 

 Microscopical Club " (vol. v., 1892-94, page 205), 

 would probably meet the requirements of Miss C. 

 M. Gibbings. The paper will not bear abridgment. 

 — W. T. Suffolk, Treasurer R.M.S., 143, Beulah Hill, 

 Norwood, S.E. ; March yth, 1895. 



Mounting Delicate Micro-Organisms. — A 

 very good way to mount Cyclops, and indeed 

 almost any small insect (ante page 21), is as follows : 

 The specimen should be killed in diluted spirit and 

 allowed to remain in it for some hours, it should 

 then be gently washed if requisite. Pour off the 

 spirit and rinse with water two or three times, and 

 soak in glycerine much diluted with water, leave it 

 in this for a day or two ; the water will evaporate 

 gradually and should be replaced with pure 

 glycerine, the whole process being more effectual 

 if done slowly. Mount in glycerine jelly. The jelly 

 as usually sold is too strong, it should be thinned 

 with a little pure glycerine to avoid shrivelling 

 delicate specimens. Methylated spirit, as now 

 sold for burning, does not answer for preparing 

 and preserving specimens, it turns thick and milky 

 in contact with water. Spirits of wine (about 6o° 

 over proof) should be got from a good chemist, but 

 is rather expensive. As a substitute common gin 

 or whisky answers for many purposes, but is very 

 much weaker. — Jas. Burton, 90, Theobald's Road, 

 London, W.C. 



Mounting Micro- Organisms. — Replying to 

 Miss Gibbing's inquiry, such large micro-organisms 

 as Cyclops, Daphnia, insect larvae, etc., and even 

 small fish and tadpoles can readily be preserved 

 by placing them in ten per cent, formalin, and 

 mounting in the same fluid on a slip with a hollow- 

 ground cell. In some cases it is advantageous, 

 before placing in formation, to kill and fix the 

 animals with very weak J to J per cent, osmic acid, 

 for one half to two minutes, not longer ; and wash 

 out at once in several changes of water. The cover- 

 glass is fastened with Miller's Coutchouc Cement 

 after the superfluous fluid round the edge has been 

 taken up with blotting-paper. Formalin is very 

 cheap, and is obtained in commerce as a forty per 

 cent solution. Of course, by diluting with three 

 times its volume of distilled water, one obtains a 

 ten per cent, solution, which keeps well for any 

 length of time. — C. F. Rousselet, 27, Gt. Castle Street, 

 Regent Street, London, W. 



Vegetable Sections.— J. Stephenson will find 

 Strasburger's "Handbook of Practical Botany" 

 (Swan, Sonnenschein and Co., price about 7s.) 

 gives excellent and complete directions for prepar- 

 ing and mounting vegetable sections and general 

 botanical work. — James Burton, London, W.C. 



Vegetable Sections and Mounting Micro- 

 organisms. — "Section Cutting," by Dr. Marsh, 

 will probably be useful to Mr. J. Stephenson. For 



mounting Entomostraca and small aquatic larvae, 

 I have found the following to give good results : 

 Fix with bichloride of mercury, thoroughly wash 

 and mount in No. 2. No. 2. salicylic vinegar — 

 pyroligneous acid, 100 parts; salicylic acid, 1 part. 

 No. 2, salicylic vinegar (as above), 1 vol. ; dilute 

 glycerine (glycerine 1 vol., water 4 vols.), 10 vols. ; 

 Farrant's medium, 11 vols. The foregoing was 

 given in a number of Science-Gossip for 1885, I 

 think, and I have found it exceedingly useful. 

 For transferring the specimens from one fluid to 

 another, I find the glass fillers supplied with 

 fountain pens extremely handy.- — C. W. Maw, 

 Bradford, Yorks. 



Vegetable Sections. — The best book at present 

 published is "Botanical Microtechnique," byD. A. 

 Zimmerman, translated from the German by James 

 Ellis Humphrey (Henry Holt and Co., New York, 

 1 893) . Some account of the preparation of vegetable 

 tissues is given in "Bower's Practical Botany" 

 (Macmillan and Co.). " Lee's Microtomists' Vade- 

 Mecum (Churchill) is full of valuable information, 

 but seems to ignore the existence of plants altogether. 

 The processes used in animal histology need 

 considerable modification when employed in botani- 

 cal researches. The best results are obtained 

 generally by using alcoholic processes, and working 

 as simply as the case in hand permits ; do not use 

 four processes if three will do, and so on. Vegetable 

 tissues are very delicate and frequently resent 

 rough treatment. Only soft tissues can be cut with 

 the best microtomes ; harder substances, as stems, 

 which offer more resistance than the longitudinal 

 section of soft fir-wood or lime, are best embedded 

 in a bit of soft wood such as lime, willow, etc., and 

 then cut with an x\merican metal plane. First 

 wrap the prepared stem in tinfoil, fill the cavity 

 with melted paraffin and force the substance to be 

 cut into the cavity, set the plane very fine, keep the 

 iron very sharp, and the work wet with alcohol. 

 Place the sections in alcohol at once, and keep 

 them in spirit till they are wanted for staining and 

 mounting, do not use a piece of wood for embedding 

 shorter than four or five inches, otherwise the 

 plane will not cut well. — W. T. Suffolk, Treasurer 

 R.M.S., 143, Beulah Hill, Norwood, S.E. 



" Xanthidia " in Flint. — Some time ago, I 

 circulated round the Postal Microscopical Society, 

 a set of slides of chippings of ordinary road flints, 

 and from the interest with which they were 

 received, I gather that many microscopists are 

 unaware how easy it is to prepare these objects 

 for the microscope. Xanthidias, or, as they have 

 been more recently termed, Spiniferites, can most 

 readily be obtained from any road which has been 

 newly laid with chalk flints, where some of the 

 flints have been crushed by cart wheels passing 

 over them. In such a crushed flint there will, 

 generally, be found a number of thin flakes of 

 sufficient transparency to allow of their being 

 mounted for the microscope without further 

 grinding down. On returning home, these can be 

 examined one by one in a drop of water or 

 turpentine on a glass slip under a cover-glass, and 

 those containing good Xanthidias, remains of 

 foraminifera, or spicules, can be set aside and 

 subsequently mounted in balsam. It is well to 

 mount several chips on a slide, because the cover- 

 glass will thus be better supported, and it is 

 advisable to attach them to the slide with very 

 thin gum before applying the balsam, otherwise 

 they will slip out of place. There is a delightful 

 uncertainty about hunting for these objects, a 



