SCIENCE-GOSSIP. 



179 



conducted several experiments on the air of school- 

 rooms, the results of three of which are well 

 illustrated in fig. 3. Experiment a was made 

 before the school assembled, b in the middle of 

 the day, and c when the school was closed. 



Sponge Spicules. — The common freshwater 

 sponge, Spongilla jiuviatilis, contains spicules of two 

 forms, one with two discs like serrated wheels 

 united by an axle, the other slightly curved, pointed 

 at each end, and rough on the surface. They are 

 silicious, and may be separated by the use of nitric 

 acid. Another sponge, Grautia compressu, which is 

 very small and white, and is usually to be found 

 attached to seaweeds, contains two forms of 

 spicules, both of which are calcareous. In this case 

 liquor potassae must be employed to obtain them. 

 One form is tri-radiate, and the other club-shaped 

 at one end and pointed at the other. The spicules 

 of both sponges are very beautiful in form, and 

 would well repay the time spent in extracting them. 



Nerves of Mouse's Ear. — There is no cuta- 

 neous structure throughout the entire mammalian 

 series that is so 

 richly supplied with 

 nerves as is the ear 

 of a mouse. It has 

 been estimated that 

 one ear contains 

 about 12.000 nerve- 

 knots. On dividing 

 the cartilage of the 

 ear horizontally, so 

 that the ear is split 

 into two lamellae, 

 no less than four 

 nerve plexuses may 

 be seen in each. 

 Lying en the car- 

 tilage are the larger 

 trunks, which usu- 

 ally divide dicho- 

 tomously, and in- 

 tercommunicate 

 in seven different 

 fashions. The 

 second layer, like 

 the first, is com- 

 posed of medullated 

 fasciculi of smaller 

 freely inter- 

 communicating with each other, and lying 

 immediately beneath the capillaries. The third 

 layer is composed of still finer medullated 

 fasciculi, and is on a level with the capillaries. 

 Small fasciculi of this layer, composed of from 

 four fibres, run to hair follicles, and, having 

 encircled each with one or several turns, terminate 

 in a little nervous coil, knot, or glomerulus ;i( Its 

 base. The nerve-knot are spherical with a 

 diameter of al>out 0015 of a millimetre, and they 

 occasionally include a few ganglion cells in their 

 inter. 



Hai* ■-. —Hairs should be washed (nol 

 soaked) in liquor all ohol and 



water, thoroughly <.'r , aked i" 



turpentine for several days. 'Ihey may then 1": 

 mounted in the usual way in balsam. 



In 



Ions, v.)iir.h bas been published in 

 ■ opi( ■>! 

 offers some valuable suggi 



Fig. 3.-MICROB 



d, algae; 6, cells of cryptogams; 



on the preparation of balsam for mounting. Balsam 

 in its commercial state contains many volatile 

 principles and traces of acids, which in the course 

 of time act upon the specimen and diminishes or 

 entirely removes the colour. All this may be 

 lessened if the balsam be heated sufficiently to 

 drive off the volatile constituents, or more thor- 

 oughly obviated if a little potassium-carbonate or 

 mild alkali be added to neutralize the acid just 

 before the balsam is heated. When the balsam 

 becomes hard it can be broken into flakes and 

 stored. When wanted for use dissolve in xylol to 

 the desired consistency and filter through absorbent 

 cotton. 



Separation of Diatoms, Mineral Particles, 

 etc — For the above purpose the " Zeitschrift fur 

 Augewaudte Mikroskopie " recommends the fol- 

 lowing liquids of high specific gravity : Brown's 

 Liquid (methylene iodine), which has a specific 

 gravity of 3'3- By adding iodoform to this, this 

 figure is raised to 345. whilst iodine increases it 

 to 3^65 ; Klein's Liquid (potassium-boro-wolframin), 



the specific gravity 

 of which is 32S ; 

 Rohrbach's Liquid 

 (barium- mercury 

 iodine), specific 

 gravity 358 ; Tou- 

 let's Liquid 

 (sodium - mercury - 

 iodine specific gra- 

 vity 319. All of 

 the above are solu- 

 ble in or miscible 

 with water in every 

 proportion. In 

 using them the ma- 

 terial is thrown on 

 the liquid, which 

 floats or sinks 

 according to its spe- 

 cific gravity. 



A Mystifying 

 Fungus. — The re- 

 production of the 

 truffle is a perplex- 

 ing problem for mi- 

 croscopists. Some 

 land-owners of Lot 

 and Correze have 

 been experimenting to determine whether the 

 spores are not diffused through the intermedium 

 of cattle, and particularly of certain domestic 

 animals of quick digestion, but M. Grimblot seems 

 to have proved that the diffusion of the spores is 

 effected by wood-mice. This throws doubts upon 

 another common belief, that both this valuable 

 I 11 and the common mushroom produce spores 

 .; ii li will not develop until passed through the 

 intestines of a cow or horse. 



i.lycerine, either pure or mixed 



with water or alcohol, is frequently used to pre- 

 Berve tbe larvae of delicate insects, it preserves 

 the colour and form belter than alcohol, but 

 partii nlarly in the 1 ase of larvae if causes a Bof ton- 

 ing of the tissues, unless great can I"- observed. 



Microscopical Studies, fn answei to the 

 query (anti o (48), Mr, [arnea Eiornell has com 

 his in il aei ies "i botaoii &! slides, with 

 itlve letlei pre 11 . and illusti ated by mil ro 



f, and the se' oiid i'. now about ready, He 

 ias also a ill ■■ sei Ies Illustrating mm ine zoology 

 1 j ; tnr,{ Hall, E 11 1 



-s in Am of Si 

 c, spores 01 cr> 1 



x 500. (Miquel 



