88 



HARDWICKE'S SCIENCE-GOSSIP. 



It cannot be given to our British species as a 

 means of obtaining food by indirect means, as in 

 the imago state the insect sustains itself by tender 

 plants. Rye says the perfect insect devours 

 mollusca. 



It may have been given by Nature merely as an 

 ornament, not influencing the economy of the 

 insect, but "for the same reason," says the Rev. 

 J. G. Wood, "that the butterfly's wing glows with 

 many-coloured plumage, and the rose is dowered 

 with softly-tinted petals and sweet perfume." 

 ("Insects at Home," p. 135.) 



I think this is the most philosophical way of 

 looking at it. Why must everything that Nature 

 grants have a use ? 



Knapp, in his "Journal of a Naturalist," states 

 that glow-worms shine faintly after the 14th July. 

 This is not always the case, as I have observed 

 them shining quite brightly late in August ; nor 

 was it after a shower of rain, the previous days 

 having been remarkably hot and dry. A lady tells 

 me that at Hastings, the gardens of poor people, 

 during the mouths of July and August, sometimes 

 have many of these insects scattered about them. 

 At night, the moving dots of light must have a 

 very pretty effect. Some of our readers will pro- 

 bably think of the lines occurring in the " Merry 

 Wives of Windsor :" 



" And twenty glow- worms shall our lanterns be. 

 To guide our measure round about the tree." 



I^ottuig-hill. 



E. Halse. 



MICROSCOPY. 



Mounting in Glycerine Jelly. — Permit me to 

 supplement the remarks of your correspondents on 

 the method of mounting in this medium, which I 

 have employed for some time for mosses. The great 

 difiiculty is in cementing the glass cover, as most 

 of the cements used have a great tendency to "run 

 in." The method I employ, and which I find to 

 answer perfectly, is that given at page 45 of that 

 excellent little work on " Microscopical Manipula- 

 tion," by Mr. W. T. Suffolk. This consists in using 

 what is known as electrical cement, and as there 

 may be many of your readers who do not possess 

 this useful work, I make free to append the method 

 of making and using it as there given. "Melt 

 together five parts of rosin, one part of bees-wax, 

 one part red ochre, and two parts of Canada 

 balsam; mix well, and pour-into pill-boxes of con- 

 venient size. This cement is most conveniently 

 used with a miniature solderiug-bit." I use a piece 

 of thick brass wire beaten out at one end to a flat 

 surface, and then filed off to the requisite or most 

 convenient width,— say, not more tiian one-eighth of 

 an inch. Tliis should be moderately heated in the 

 flame of a spirit-lamp, a portion of the cement 



taken up by it, and laid along the edges of the 

 covering glass till it is cemented all round. It may 

 then be smoothed off by heating the " bit " to a 

 greater temperature, and running it round the edges 

 until a neat, smooth surface is obtained. As this 

 cement, however, is very brittle after it has set, 

 which it does [as soon as cold, a rim of gold-size 

 should be run round it, which will make it perfectly 

 adhesive, and render it quite safe from cracking. 

 Mr. Suffolk adds, at page 55, " This system of 

 compound cementing answers perfectly ; the elec- 

 trical cement having in the first instance no tendency 

 to run in, and the gold-size effectually keeping it 

 from separating from the glass." As, however, it 

 is rather unsightly on the glass slides, I always use 

 the paper covers afterwards. — Charles P. Hobkirk, 

 Huddersfield. 



Sand-blast. — In the remarks on the cells formed 

 by this process, it is stated that they were adapted 

 for opaque objects or fluid mounting. The inventor 

 has called my attention to the fact that they answer 

 well for mounting with balsam, when a dry cell 

 is necessary. — F. K. 



Extracting Lingual Ribbons.— -In reply to 

 " C. P. A.," I wish to mention that I have obtained 

 the palates of very small land mollusca, such as 

 Pupa marginata, by crushing shell and all between 

 two glass slides and examining the mass, extended 

 by pressure, with the microscope. The palate will 

 soon be detected by its reticulated appearance, and 

 the portion containing it parted from the rest. 

 Two or three trials will enable the lingual ribbon 

 to be cleared from the surrounding tissues. A 

 bristle is the safest tool to use. — George Guyon. 



Remounting Injections. — Allow me to inform 

 your correspondent, W. Statham, that the best way 

 of remounting the injections he refers lo in your 

 number of last month, is to allow them to get 

 thoroughly dry and mount in balsam, after satu- 

 rating them in benzole. I have many beautiful 

 injections which I remounted in this way about 

 twenty years ago. — Thomas Brittain. 



Cells for Microscopic Objects. — Many 

 objects, when mounted in balsam, require some kind 

 of cell to prevent undue pressure and the conse- 

 quent result ; viz. fracture. Paper and thin glass 

 have been used for such purposes, but there has 

 always been the difficulty of maintaining these in 

 position when the slide is heated sufliciently to 

 harden the balsam. In order to avoid this difiiculty, 

 I make the cells with a mixture of common whit- 

 ing, mixed with gum- water to about the consistence 

 of good cream : this will work freely with a camel- 

 hair pencil ; and cells from the thickness of writing- 

 paper to stout card can be as readily and expe- 

 ditiously made as with the ordinary asphalt varnish. 

 This mixture is also very useful for " ringing " the 



