HARDVVICKE'S SUIEN CE-GO SSIP. 



161 



with the same tiling, and that sometimes a quantity 

 of seemingly good slides would two days afterwards 

 be faulty. Mr. Laing deserves the thanks of all 

 who occasionally meet with the difficulty, for telling 

 us of the remedy.—^. P. P. 



PoLARiscopic Objects. — Having my attention 

 drawn to some crystalline substance attached to the 

 stamen of the white Azalea flower, which I found to 

 be hard and very transparent, I placed it under 

 the microscope, and, from its appearance, I thought 

 it very likely to be a good subject for the polari- 

 scope, and so it has proved. On crushing the mass, 

 every particle showed beautiful colours, except at 

 the fracture, which appeared black ; I suppose in 

 consequence of the ray of light being refracted by 

 the broken crystals. I then applied a drop of clear 

 water, in which it slowly dissolved, at the same 

 time retaining the brilliant colours until quite dis- 

 solved, when it became as colourless as the water. 

 I then placed it under a glass to prevent dust settling 

 on it, and it very slowly again crystallized in beauti- 

 ful stellated forms iu about forty-eight hours. 

 Under the polariscope it produced the most gorgeous 

 colours imaginable. On opening the flower of the 

 Azalea, a drop of very clear saccharine liquor may 

 be obtained ; put this on a glass slip without adding 

 water, and it will show the very beautiful crystals 

 in a few hours. On having this substance analyzed, 

 it proved to be perfectly pure sugar. — James 

 Fullagar. 



A "Life Slide."— Mr. D. S. Holman, of Phila. 

 delphia, has recently brought out a " life slide," in 

 which living objects of a certain size can be retained 

 under observation for weeks together. A current 

 of water is made to flow continuously through the 

 chamber containing the object, so that the processes 

 of respiration, circulation, nutrition, &c., as well as 

 the eifects of certain poisons, can be studied under 

 perfectly natural conditions. The transparent 

 chamber in which the animal is contained has a fine 

 perforation at each end, too small to allow of the 

 escape of the animal, but sufficient to maintain a 

 flow of water. The latter is effected by means of 

 tubes and glass jars, or reservoirs, on the siphon 

 principle. An illustration of this "life slide" 

 appears in the American Naturalist for April. 



Stetjctuee of the Potato. — Mr. T. Taylor has 

 recently shown that the vascular bundles in a potato 

 may be easily seen by cutting a potato in two 

 through its axis (the section also passing through 

 some of its " eyes " ), and coating the cut surface, 

 first with a solution of bichromate of potash, and 

 afterwards several times with a strong tincture of 

 iodine, which will stain the starch blue, but leaves 

 the vascular bundles yellow. The air-ducts will 

 then be seen to extend invariably to the eyes. For 

 microscopical study these sections are to be made 



and treated with a strong acid or caustic alkaline 

 solution, which will dissolve the starch, but leave 

 the bundles unaltered. The sections may thea be 

 mounted as usual. To isolate the vascular bundles, 

 place a potato, skinned wilhout wounding the 

 "eyes," in a solution of sugar and water (two 

 ounces to the pint) and keep it at a temperature of 

 72° P. for nearly a fortnight. The fungus of ferment- 

 ation will reduce the potato to a pulp, except the 

 vascular bundles, which may be mounted in gum or 

 balsam, and studied with a power of one hundred 

 diameters. 



ZOOLOGY. 



Akgas keflexus.— This arachnid is the Ixodes 

 marcjinatus of Pabricius, Rhynchoprion coUmhce 

 of Hermann, and Arg^s rejlexus of Latreille, — not 

 kxgus, which is a genus of Phasianidse, as inadver- 

 tently printed in your last number. How truly the 

 specific name of "marginatus" applies, is well 

 shown in Mr. Pullagar's drawings. And it is note- 

 worthy that these are the first engravings ever pub- 

 lished of Argas in England, and that they are far 

 better than any to be found elsewhere ; facts surely 

 creditable to the author as well as to Science- 

 Gossip. It seems curious that, after this Canter- 

 bury Argas had been submitted, year after year, to 

 all the most eminent experts in London, it should 

 be left to the perseverance of Mr. Gulliver, jun., 

 with the aid of Professor Westwood, to establish 

 this species as new to Britain, though well known 

 on the Continent. Prom all that appears, Argas 

 rejlexus is harmless; yet Argas persicus, which 

 lives in houses in Persia, is said to be a dreadful 

 creature, occasioning, by its puncture in the human 

 subject, convulsions, delirium, and even death. Now 

 the Canterbury Argas has been so well engraved 

 and described in Science-Gossip, probably the 

 same species will be found and recognized iu other 

 British localities.—^. B. 



" Utilizing " Poisonous Snakes.— Probably no 

 more ingenious method of committing murder -was 

 ever devised than one which is not unfrequently 

 resorted to by the natives of Bengal. As it is, I 

 am sure, new to most of the readers of Science- 

 Gossip, and will have a ghastly interest to all, I 

 will briefly describe it. There is in that part of 

 India a class of gipsies, who are well known to be 

 skilful snake-charmers. To one of these men the 

 would-be murderer applies, and in return for a 

 trifling fee is speedily furnished with a living cobra. 

 In order that he may be enabled to handle the veno- 

 mous creature with safety to himself, it is secured 

 in the following manner : — "A bamboo is cut from 

 the jungle of the length required, of course as long 

 as the cobra. Then the creature is shoved in, with 



