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HARDWICKE'S SCIENCE -GO SSIP. 



Examining Miceo-fungi. — I have bad the good 

 ortune to meet with a considerable gatlieriiii? of 

 that rare and interesting Micro-fungus Xenodochiis 

 carhonarius, and intend to refer to it in your 

 exchange column. In the mean time allow me to 

 say, for the information of beginners in this depart- 

 ment of microscoi)ic study, that the best way of 

 examining temporarily this and other smuts or 

 brands, is to place a small portion in water on a 

 glass slide, and try the various powers, always 

 beginning with the lower ones. — T. Brittain. 



EixiNG Diatoms.— I have found out a better 

 plan for fixing diatoms since I wrote the article 

 inserted in last month's Science-Gossip. The 

 plan is as follows :— Place the frustules in the 

 centre of the slide in a very minute drop of very 

 thin balsam. Then hold the slide over the lamp 

 till the balsam smokes. Then arrange the diatoms 

 with a hair before the balsam stiffens. Let it cool, 

 put the cover on, let the balsam run in, and then 

 bake. This plan does not do for devices, but for 

 ordinary slides of selected diatoms it will give 

 great satisfaction. — /. K. Jackson. 



Staining Vegetable Tissues.— In a paper by 

 C. Johnson, M.D., Baltimore, U. S. A. (published 

 in the Monthly Microscopical Journal, vol. xii., 

 p. 184), the following directions are given for pre- 

 paring a lilac or violet stain for vegetable sections 

 and tissues:— "Ordinary logwood extract is finely 

 pulverized in a mortar, and about three times its 

 bulk of alum (in powder) added ; the two ingre- 

 dients are well rubbed up together, and mixed with 

 a small quantity of distilled water. The complete 

 admixture of the alum and hsematoxylin is necessary, 

 and this will require fifteen to twenty minutes' 

 vigorous trituration. More water may now be 

 poured on, and the solution, after filtration, should 

 present a clear, somewhat dark, violet colour. If a 

 dirty red be obtained, more alum must be incor- 

 porated, and the mixture again filtered. After 

 standing several days, add 75 per cent, of alcohol, 

 in the proportion of two drachms to one ounce of 

 fluid. This fluid colours very rapidly, requiring but 

 a few minutes ; but if a slower tinting is required, 

 the fluid may be diluted with a mixture of one part 

 alcohol and three parts water. Before staining, it 

 is necessary to destroy any calour that may pre- 

 viously exist in the sections, &c., to be stained. 

 This, in the case of sections, may be done by soak- 

 ing in strong alcohol; for thin leaves and fresh 

 green sections the bleaching is to be accomplished 

 through the agency of Labarraque's solution of 

 chlorinated soda, in which the objects ought to be 

 macerated until perfectly achromatic and trans- 

 parent. They sliould then be transferred to distilled 

 water for an hour or two, and afterwards soaked in 

 a three per cent, aqueous solution of alum, and 

 Then transferred to the strong solution." 



Cymbella Ehrenbergii, &c.— The improve- 

 ments made in the resolving power of objectives 

 led to the discovery of delicate markings on many 

 species of Diatomaceae, which the earlier micro- 

 seopists supposed to be "smooth." To resolve 

 these delicate markings they must have a large angu- 

 lar aperture, and light of more or less obliquity is 

 required. Those forms with coarse lines not re- 

 quiring these adjuncts were easily resolved by very 

 imperfect objectives which did not admit of the 

 use of an oblique pencil of light. As oblique light 

 was not necessary for the resolution of these coarse 

 lines or costge, it does not seem to have been used 

 upon those forms possessing them. Some years 

 ago I called attention to the fact that if the costaj 

 of Pinnularia peregrina were examined with a high 

 power (one-eighth) and oblique light, a series of 

 fine lines would be found crossing them in a trans- 

 verse direction. I have since examined many other 

 forms with continuous lines or costse, and in several ' 

 cases have been able to detect finer lines upon 

 them ; and I would particularly call attention to 

 th.e co?,idi ov Synedra robmia and Ci/mhella Ehren- 

 hergii. If a valve of either of these forms is 

 examined by oblique light, the coarse, rib-like line 

 will be found to be composed of a series of com- 

 pressed beads, reminding one of a row of peas in a 

 well-filled pea-pod ; the lines on ^S*. robasta are more 

 dilficult of resolution than those on C. Wirenbergii. 

 I may perhaps remark that other species of the 

 genus Cymbella show similar markings. I have 

 not hitherto been able to detect any markings on 

 Pinnidaria nobilis, P. major, P. cardinalis, or 

 P. alpina. On P. cyprinus there appeared faint 

 traces of transverse lines.— I may here correct an 

 error hi my paper on the Diatom Erustule (No. 117, 

 September 1, 1S7-1). Fig. 135 is a section of 

 Burirella, and fig. 136 a section of JSfitzschia. — F. 

 Kit ton. 



Chlorophyl in Spongilla.— Mr. Sorby, E.R.S., 

 and E. Bay Lankester, have been recently inves- 

 tigating this subject. In the last number of the 

 Quarterly Journal of Microscopical Science, the latter 

 states, as the result of recent examinations, that he 

 found among the ama-biform sponge ])artioles of a 

 green - coloured specimen o[ Spo)?giUa, some com- 

 posed of naked, colourless protoplasm, throwing 

 out absolutely hvaline lobose pseudopodia. The 

 outline of the nucleus is not strongly marked, but 

 the nucleolus is obvious enough. In others were 

 two, three, or four, or a crowd of even twenty 

 green - coloured granules, of a uniform size and 

 peculiar form, being concavo-convex discs or cups. 

 The usual colour of Spongilla is a pale salmon. It 

 might be suggested that the green granules (the 

 chlorophyl-bearers) are parasitic, as has been sug- 

 gested in the case of the starch-bearing yellow cells 

 of Badiolarin. In the colourless Spongilla, however. 



