SCIENCE- GOSSIP. 



89 



the desmids will collect on the top of the sediment, 

 where they will increase and multiply. The surface 

 layer containing the desmids may then be drawn 

 off with a syphon and cleaned as before. A some- 

 what similar rocking process is useful for separating 

 foraminifera from sand, but the rocking must be a 

 little more violent, when the sand is left behind, 

 unlike the flocculent matter in the desmid gather- 

 ings, which is swept forward by the water. The 

 foraminifera are not, of course, so easily distin- 

 guished by the eye. In mounting, Dr. Bryan 

 makes a small box of parchment paper, about 

 1J inch by 1 inch, and places the water containing 

 the desmids in the box, which is then floated on 

 glycerine. In two days the water will have dif- 

 fused into the glycerine, and sufficient glycerine to 

 penetrate the desmids will have passed through 

 the parchment into the box. By this ingenious 

 method the desmids will undergo no contraction. 



Mounting Marine Algae. — I submit the 

 following few notes on preparing and mounting 

 marine algae, which originally appeared in the 

 ". International Journal of Microscopy and Natural 

 Science" in October, 1894, hoping they may induce 

 some to take up the study of these beautiful lowly 

 plants. I will assume that we have collected a 

 number of different species, either from the sea- 

 shore after a breeze or from the rocks at low tide ; 

 ,as soon as possible on reaching home we proceed 

 to examine our treasures. Have ready a couple of 

 basins, a soup plate, and a couple of saucers ; put 

 into the basins and plate some sea water, or salt 

 and water made by well stirring some common salt 

 in a jug of fresh water ; let it settle and then pour 

 off. Wash the algae well in No. 1 basin and 

 rinse in No. 2, carefully spread and float out the 

 frond in the plate, and examine with a lens. Any 

 tips or branches of the frond that we see have fruit, 

 and any of the smaller algae we will examine under 

 the microscope by floating them on to a glass slip, 

 3 in. by 2 in.; the larger mass we will float out on 

 paper as an herbarium specimen. Having detected 

 those pieces bearing repi-oductive organs, etc., 

 which we desire to mount as microscopic objects, 

 we place them in a saucer with clean fresh water, 

 and after a few minutes float a portion on to an 

 ordinary 3 in. by 1 in. slip, and after removing it 

 from the water we dry it with a linen rag, wiping 

 off the water, and with a piece of blotting-paper 

 soak out all the water we can from the algae. 

 Have ready your clean cover-glasses and medium. 

 Now gently warm the slip with the piece of algae 

 on it, and put a drop of the medium on to it ; then, 

 again warming the slip and cover-glass, place the 

 latter carefully on to the object, tilting it on so as 

 to drive out any bubbles. Lay the slide by for a 

 few hours until the medium is set (it may remain 

 several days) ; then, if satisfactorily done, clean off 

 all the superfluous medium with sponge and warm 

 water, ring it first with gold size and then with 

 white zinc cement, finish with a named label, and 

 we have a slide worthy of a place in any cabinet. 

 I have found Deane's medium to be the best for 

 preserving the colour and structure of the cells. 

 It is made as follows : — Gelatine, 1 oz. ; honey, 

 5 oz. ; water, 5 oz. ; rectified spirit, § oz. ; creosote, 

 ■6 drops. Soak the gelatine in the water until soft, 

 add the honey, then boil the mixture. When it 

 has cooled somewhat, the creosote mixed with the 

 spirit is added. Lastly, filter through fine flannel. 

 The medium is used warm. I have tried glycerine 

 jelly, and discarded it on account of its dissolving 



all the colour out of the algae. Canada balsam is 

 useless, as the object must be dried, thus shrinking 

 and distorting the structure of the cells. In Deane's 

 medium we have the material which, so far as my 

 experience goes, is most suited for these beautiful 

 weeds.— John T. JVeeve, 4 Sydenham Road, Deal. 



Micrographic Fly-cage.— The "Journal of the 

 Boyal Microscopical Society " describes and illus- 

 trates the apparatus exhibited at the meeting of 

 the Society on February 20th (see S.-G., Vol. VII. 

 p. 342), devised by Mr. G. H. Kogers, and made by 

 Mr. C. Baker of High Holborn, for exhibiting the 

 proboscis of the common house-fly as an opaque 

 object. It is large enough for the blow-fly, but can 

 be made anv size. It consists of a brass cone 



^.■Jor-y 



Fig. 1. Micrographic Ply-cage. 



soldered to a brass plate with a hole in it, just 

 large enough to admit the head of the fly, which is 

 surrounded by a disc of ivory let into the plate. 

 The fly is gently pushed into the cone with a little 

 piece of wool behind it, and is ready for examina- 

 tion. A little treacle or honey is put on to the 

 ivory disc ; the fly puts out its proboscis, which is 

 kept flat and in one position. It is very easy to 

 focus, and requires no more adjustment of the 

 object than an ordinary slide. 



Mites in Microscopic Slide. — I have a slide 

 of • a portion of the polypary of a Californian 

 zoophyte (Membranipora tuberculata) mounted as 

 an opaque object for top-light. It is in a cell 

 which is securely sealed by an ornamental paper 

 with an opening to show the object, but otherwise 

 covering the 3x1 glass slide thoroughly and 

 effectually, the object being hermetically sealed. 

 I have no record of the preparer, except that it is 

 not my own work. The slide has been in my 

 cabinet for certainly not less than ten years, and, 

 until a day or two since, for a very long time I 

 have not seen it under the microscope. On this 

 occasion I had it under the 2-inch and brilliantly 

 lighted by the side-reflector, when some moving- 

 object in the cell caught my attention. This 

 moving, living object proved to be a mite, which 

 was active and vigorous, and, so far as I could 

 examine it, resembled the cheesemite (Tyro- 

 glyphus domesticm). It was not alone, for I quickly 

 discovered another, equally lively, and on looking 

 closely I found two exuviae and what looked liked 

 portions of others. The object in which these 

 mites have been carrying on their life-histories is 

 about ^th of an inch square, and presents on the 

 surface 360 thecae, or cells — a sufficiently big- 

 world for two or three organisms so tiny — but 

 whence came they, and whence their supply of 

 oxygen and food? These are questions which 

 puzzle me. — F. R. Broltenslure, Exeter. 



[If we understand our correspondent aright, the 



