230 



HARD WI CKE 'S S CIENCE - G OSSIP. 



surprised to see the creature adroitly bring the head 

 down to the spot (fig. 176, a) where there appeared more 

 space between the body and the silk cord than at any 

 other point, and it quickly withdrew the head out from 

 inider the cord, and placed itself in the position of 

 fig. 1 75, with the cord, at /', complete : this process 

 occupied about twenty-five minutes. In this state it 

 rested until the chrysalis was fonned, when the old 

 skin was thrown off from under the cord, and the 

 chiysalis left as shown (fig. 177), from which in due 

 time the butterfly will emerge. 



Canterbury. J. Fullagar. 



MICROSCOPY. 



Raphides. — Would one of the many readers of 

 Science-Gossip kindly inform me in what way 

 turpentine acts on vegetable tissues, so as to make 

 them transpai-ent ? Some time ago, being desirous of 

 obtaining a good slide of the outer coating of an 

 onion, showing the raphides for the polariscope, I 

 soaked it for several weeks in spirits of turpentine, 

 after which, when taken out to mount, it ^^•as, with 

 the exception of a few very small opaque spots, 

 transparent. However, when it had been in balsam 

 for some hours, these spots which were left became 

 larger, so that in time the structure would have 

 regained its original opacity. I therefore repeated 

 the experiment, but with the same results. I may 

 add that it was mounted in balsam dissolved in 

 benzole. Of course it was of no very great conse- 

 quence, as it still shows the crystals pretty well ; 

 but I suppose, as a general rule, for the polariscope 

 tissues cannot be made too transparent. While upon 

 the subject of Raphides, may I suggest a plan which 

 I have found answers well for making very interest- 

 ing slides of those from the rhubarb. Take a stick 

 of rhubarb, and, after peeling it, cut about two 

 inches off, and again divide this into pieces a quarter 

 of an inch thick. Put these into a test-tube and 

 half fill with distilled water ; boil or simmer till 

 they become quite stringy, then, after emptying the 

 tube of its contents, gently pour off the surplus fluid. 

 Now, if a drop of liquid be squeezed from the re- 

 maining mass, put on to a slide with a covering- 

 glass, and submitted to the microscope, isolated cells 

 will be seen, many of them having in their interior 

 the aforesaid raphides. Generally there are some 

 loose ones as well, so that one has the opportunity of 

 seeing them singly or in situ. As to preserving, my 

 way of mounting is in fluid, by mixing the liquid 

 containing them with a solution of carbolic acid, 

 adopting Mr. Suffolk's plan of making a cell of thick 

 damar varnish, and putting on the cover while it is 

 yet sticky. The only fear is, I think, whether enough 

 carbolic acid can be introduced into the cell to pre- 

 serve its contents. There is, perhaps, nothing very 

 new in all this ; but for those who are only beginners 



in mounting their own objects, the foregoing direc- 

 tions may prove useful. — E. W, JF., Le^vis/iam. 



Plants for Raphides, &c.— In last September 

 number of the "Monthly Microscopical Journal" 

 Professor Gulliver gives a list of the plants, chiefly 

 British, in which these and other microscopic crystals 

 may be most conveniently examined and discriminated. 

 The orders and families are noted according to 

 Babington's " Manual of British Botany," so that the 

 student may at any time select a plant in which to 

 examine any of the particular forms of ciystals. These 

 are as follow : — For i., Raphides — Balsaminacese, 

 Onagracece, Rubiacece, Dioscoreacese, TrilliaceDe, 

 Orchidacece, Amaryllidaceje, Asparagaceje, Liliacece 

 (part of), Typhacete, Aracece (part of), Lemnacese 

 (except Wolfifia), Vitacere, Hydrangia, Veratrum. 

 For ii., SphcerapJddes — Caryophyllacese, Geraniaceas, 

 Celastracece, Rhamnaccse, Myriophyllum, Parony- 

 chiaceae. Viburnum, Mercurialis annua, Chenopo- 

 diacece (part of). Rhubarb, Urticete, Passifloracese, 

 Cactaceae, New Zealand Spinach, Pulp of Pear. For 

 iii., Long Crystal Prisms — The pericarps of Compositse 

 leaves of Iridacece, Fourcroya, Sweet Orris, Guaiacum 

 bark, Quillaja bark, bulb-scales of Onion, Shallot, 

 Garlic, and Leek. For iv.. Short Prismatic Crystals — 

 Pericarps of many Composite, leaves, &c., ofTiliacese, 

 Aceraceae, Amentifer^e, Leguminosse, testa of the 

 Elm, Anagallis, and Tamus. Figures of the different 

 crystals were given in Science-Gossip, May, 1873, 

 except the short prisms, of which there is a plate in 

 the " Monthly Microscopical Journal" for December 

 of the same year. But the present list will afford an 

 inexhaustible collection of materials for microscopical 

 amusement and instruction, all remarkable, too, for 

 their interest and beauty. As regards their distinctive 

 characters and taxonomic value, remarks are added 

 in the " Monthly Microscopical Journal." When not 

 otherwise mentioned, the raphides, &c., are to be 

 looked for in the leaves or sepals. 



Life History of the Simplest Organisms. — 

 At the recent British Association meeting the Rev. W. 

 H. Dallinger delivered an exceedingly interesting 

 lecture on " Researches in the Life History of the 

 simplest Organisms." He stated that he had worked 

 out the life histories of six monads, and then pro- 

 ceeded to give the results of numerous experiments in 

 connection with the same. Motion was, perhaps, 

 nowhere so universal as in the most minute forms of 

 life, and here it was that we often found movement 

 of the most graceful kind. It had now been made 

 quite certain that the degrees of ease and force of 

 motion of these animals depended upon the number 

 of their flagella, which, so far as investigation had yet 

 gone, ranged from one to four. With regard to the 

 most minute forms of life, Mr. Dallinger said that the 

 study of their life histories showed that these forms 

 were perfectly complete and definite ; there was no 

 mutation nor anything unnatural. The results of his 



