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HA RD WICKE' S SCIENCE- G OS SI P. 



two more statoblasts, and adjust them round the 

 foregoing (or on a separate slip, if preferred). Add 

 a drop or two of benzole or turpentine to keep them 

 in place, and when dry, which will be in a few 

 minutes, add Ch 3, cover with thin glass, previously- 

 just warming the cover ; put the slide in a warm 

 place for some hours to harden, and it will then 

 be ready for examination. See J. Q. M. Club, 

 Series II. vol. i. p. 173 ; vol. ii. p. 252. Carpenter 

 recommends gelatine, which will set on cooling, gum- 

 arabic, spermaceti, or paraffine ; a mixture of trans- 

 parent soap is good, or celloidin. — V. A. L. 



Preparing Sections of Sponges— Mr. Sollas' 

 method. — A good representative piece of the sponge 

 is well soaked in distilled water, to remove its con- 

 tained alcohol. After this, it is placed for an hour 

 in a strong solution of gum, and then transferred to 

 the well of a freezing microtome. Sections of any 

 required thinness can now be cut in the usual way, 

 the razor passing with apparently equal facility 

 through the soft tissues and the hard spicules. Some 

 of these slides — stained and unstained- -Mr. Sollas 

 mounted in glycerine, others in C. Balsam, after 

 successive treatment with absolute alcohol and car- 

 bolic acid and turpentine. Before preserving sponges 

 in spirit, he recommends a preliminary soaking in a 

 •02 or -03 per cent, solution of osmic acid (Os 4 ), 

 as the histological characters of the specimens are 

 thus less injured. — V. A. L. 



Sections of Sponge. — I should fancy Mr. Clark 

 would find celloidin a suitable imbedding medium, 

 as it does not need to be dissolved out, being quite 

 transparent. Celloidin is manufactured by Schering, 

 of Berlin, and is to be obtained in cakes (2s. 6d., I 

 think), from A. & M. Zimmermann, 21 Mincing 

 Lane, London, E.C. The general method of using 

 it is as follows : — A portion of the cake is broken 

 into small pieces, and dissolved in equal quantities 

 of absolute alcohol and ether. The solution should 

 have the consistence of "golden syrup." In order 

 to prepare the substance to be imbedded, it should 

 be placed for some time (a day or so) in absolute 

 alcohol, and then transferred to ether for from half- 

 an-hour to one hour, or even two hours, according 

 to its (the object's) density. The object may now 

 be placed in the celloidin solution, where it is left 

 for a period varying from three hours, or less, to 

 twelve hours, or more, according to the density of 

 the tissue. When the substance is quite permeated 

 by the celloidin, it should be placed on a piece of 

 cork, adapted for fixing to the microtome, and on 

 which is a layer of the celloidin solution. In a few 

 minutes the celloidin will set to some extent, and 

 then the whole thing, cork and specimen, is placed 

 in ordinary spirit (60 per cent.), which hardens the 

 celloidin, and in which it may be kept until a con- 

 venient time for cutting. The sections may be 

 stained and mounted in glycerine, or cleaned with 



oil of bergamotte and mounted in dammar. I should 

 say, for Mr. Clark's special purpose, it would be 

 better to graduate the changes of density of the fluids 

 more carefully, since rapid osmosis often destroys the 

 natural appearance of delicate organisms. Thus, he 

 might immerse the sponge in 50 per cent., and then 

 in absolute alcohol. Again, the celloidin solution 

 might be made much thinner, and allowed to evaporate 

 slowly to the required consistency, dust being care- 

 fully excluded. Of course care must be taken to 

 have a sufficient quantity of the diluted solution to 

 cover the specimen when it has evaporated to the 

 requisite extent. — A. IV. L. 



Extract of Logwood.— In answer to Mr. Hafen. 

 I send the following : — I. Aqueous Logwood Stain. 

 Take 60 grms. of dried extract of luematoxylin, 180- 

 grms. of powdered alum, and rub them thoroughly 

 together in a mortar, adding slowly 300 cc. of distilled 

 water ; mix carefully, and afterwards filter. To the 

 filtrate add 20 cc. of absolute alcohol, and preserve 

 in a stopped bottle. This solution should be kept in 

 a cool place for at least a fortnight before using. The 

 older it is, the more excellent it becomes. II. Gibbe's 

 Logwood. Extract of hasmatoxylin, 6 grms., alumen, 

 18 grms. Mix thoroughly ; while mixing add 28 cc. 

 of distilled water ; filter ; add to the filtrate 5j of 

 rectified spirits of wine ; let it be kept in a stoppered 

 bottle for a week before using. What remains on 

 the filter can be mixed with 14 cc. of distilled water r 

 and left soaking in it for an hour or so ; then filter, 

 and add to the filtrate 5ss of rectified spirit. The 

 second solution is as strong as the first. The alum 

 used must be potash without ammonia, and the 

 extract of hsematoxylin must be English. Besides 

 these there are Klein's logwood stain and Mitchell's, 

 which one I consider the best. They will be found 

 in J. of Postal Society, vol. iv. pp. 239, 240, and 

 from which the above recipes have been taken. — 

 V. A. Latliam, F.JM.S., Manchester. 



The Royal Microscopical Society.— The 

 February number of the Journal of the above Society, 

 besides the elaborate " Summary of Current Re- 

 searches," contains the following papers : " Twenty- 

 four New Species of Rotifera," by P. H. Gosse ; 

 "Freshwater Algae of North Cornwall," by A. W. 

 Benett ; "Improvements of the Microscope with 

 the aid of new kinds of Optical Glass," by Professor 

 Abbe ; and " Notices of New American Freshwater 

 Infusoria," by Dr. A. C. Stokes. 



Corn Bunting with Crossed Bill. — In Decern 

 ber of last year a keeper who lives near here shot a 

 corn bunting with crossed mandibles. It was feeding 

 with sparrows in a farmyard. The bill is exactly the 

 shape of that of the crossbill. The upper mandible 

 is much hooked. I have seen a rook with a crossed 

 bill, and heard of a canary. — Geo. Roberts, Loft house, 

 Wakefield. 



