86 



SCIENCE-GOSSIP. 



MICROSCOPY 



CONDUCTED BY F. SHILLINGTON SCALES, F.R.M.S. 



List of Ponds. — As a beginner who is interested 

 in Pond Life, I would like to recommend (as sug- 

 gested ante page 57) to others my favourite pools in 

 Richmond Park, Surrey. The ponds are situate in 

 most cases near to Kingston Gate, Ham Gate, Ladder 

 Stile and Robin Mood Gate. The following may be 

 found : Amoeba, Vorticella, Hydra, Rotifers, Water 

 YXt&s, Stentor polyinorphtis, I'ok'ox, etc. I may add 

 that Hydra viridis may be found in abundance in the 

 roadside ditch, near to Beverly Bridge, Putney Vale, 

 where I have taken some just recently. ^^/c/w; Pearson, 

 GUnville Koad, Norhiton, Surrey. 



Method for Ripening Hae.matoxyi.in.— Prof. 

 H. F. Harrispreparesaripenedsolutionofhaematoxylin 

 by the following means, which, in view of the frequent 

 use of this stain by microscopists, may be worth 

 trying. One grm. of haematoxylin in crystals is 

 dissolved in 10 grm. of absolute alcohol. Then a 

 second solution is made of 20 grm. of ammonium or 

 potassium alum dissolved in 200 ccm. of hot distilled 

 water. The two solutions are mixed at once or after 

 24 hours, and '5 grm. of mercuric oxide (either red or 

 yellow) is added, 'the mixture heated to boiling, and 

 then quickly cooled. The liquid at once becomes 

 dark red, and may be used for staining (if necessary) 

 without delay. A precipitate that sometimes forms 

 after a few days may be filtered off, and does not 

 reappear. 



Microscopic Preparations of Copepoda.— Mr. 

 C. D. Marsh says that copepoda and pentomostraca in 

 general are most easily collected by means of a 

 dredge, the mouth of which is covered with a cone of 

 coarse wire gauze. This gauze-covered mouth keeps 

 out the sticks, weeds, etc., so that the net can be 

 repeatedly drawn through a weedy pond without 

 becoming choked with debris. For histological 

 purposes Mr. Marsh recommends killing by one of 

 the osmic acid preparations, but for systematic pur- 

 poses, or for the study of the muscles, he has found 

 .alcohol the best killing and preserving agent. 

 Formalin leaves the material too brittle for dissec- 

 tion. The best staining results are obtained by 

 immersion in dilute picro carmine, for one to three 

 days. For dissecting, the alcohol should be 

 replaced by glycerine, but the change must be made 

 gradually or the specimen will be distorted and 

 perhaps ruined. The dissection will require the 

 finest needles, and better work can be done if they are 

 carefully ground down on two sides, so as to make 

 minute scalpels. Mr. Marsh uses almost exclusively 

 Farrant's medium for mounting, and the parts as 

 dissected in glycerine can be removed direct into this 

 medium. 



Nitragin and the Nodules of Leguminous 

 Plants. — Miss Maria Dawson states that a study of the 

 nodules found upon the roots of leguminous plants has 

 ltd her to an unhesitating confirmation of the parasitic 

 nature both of the filaments and of the bacteroids. The 

 formation of tubercles is the result of inoculation with 

 nitragin, either of the seeds or soil, and this consists 

 of minute straight micrococcus-like organisms which 

 become connected into bacteroids and straight rods. 



Movements of Diatoms. — Mr. F. R. Rowley 

 has given an abstract of Lauterborn's important work 

 on the Structure, Division and Movement of 

 Diatoms. The structure of Pinnidaria 7najor, and 

 Snrirella ealcarata is described in detail. Lauterborn 

 believes in the existence in the former species of an 

 enveloping layer of hyaline jelly, so transparent, and 

 of a refractive index so closely corresponding to the 

 surrounding water, as to be completely invisible, even 

 with the best lenses, in clear water. The motion is 

 probably due to very fine gelatinous threads, equally 

 invisible, which proceed from the central node and 

 run obliquely backwards, forming an acute angle with 

 the surface of the frustule. In other species, how- 

 ever, both these and the hyaline investment, are 

 apparently wanting. 



New Cell for Liquid Mounts. — Mr. Chas. 

 Baker, of Holborn, has sent us a glass micro-slip tO' 

 which a glass cell has been attached by some process 

 of vitrification. This should prove a practical method 

 of surmounting a difficulty that has been a constant 

 source of trouble to microscopists and we commend 

 these cells to the notice of our readers. The price is 

 4s. per dozen. 



Bete Rouge of West Indies. — Mr. W. Cran, 

 who contributed some time ago some interesting" 

 drawings of the Mycetozoa of the West Indies, and 

 also of the "chigoe" of the same locality (Science- 

 Gossip, Vol. iv. , N. S., page 361), sends us a drawing 

 of the " Bete rouge," which we herewith reproduce. 

 It also is a native of the West Indies, and is a source 

 of considerable annoyance and discomfort at certain 

 seasons of the year. It lives amongst grass, and attacks 

 anyone walking or sitting near it. The creature 

 being very small, and keeping its hold tenaciously, 

 is difficult to remove. The best remedy is to smear 

 the part with oil or 

 vaseline. The speci- 

 men illustrated was 

 picked from the top 

 of a vesicle, which it 

 had produced upon 

 the arm of a lady. 

 The colour of the 

 '■ Bete rouge," is, as 

 its name implies, a 

 bright red. It seems 

 to belong to the Tick 

 family, in which case 

 its having only three 

 pairs of legs would 



apparently indicate that it is still immature, but 

 Mr. Cran says that he has not observed any specimens 

 with four pairs of legs like an adult tick. 



How to Keei> Voi.vox. — Some time ago a corres- 

 pondent of this journal wrote stating that he had 

 succeeded in keeping Volvox glohaior in good con- 

 dition for a long time by placing the bottle containing 

 the Volvox under a rain-water .spout, so that only a 

 few drops could drip into it to replace the loss by 

 evaporation. Mr. F. Ilarrisson, of Cheadle, Staffs, 

 writes us that after trying this and many other ways he 

 has succeeded better during this dry summer, than 

 ever before, by the following simple method. In a 

 window looking west he has placed a wide-mouthed 

 bottle half full of water, and within this, but not 

 communicating with the water, the bottle containing 

 the i'oh'o.w Two or three times a week he adds a 

 teaspoonful of spring water. Mr. Harrisson has sent 

 us a tube of Volvox from this bottle. He says they are 

 at least ten times as numerous as when, two months 

 ago, he collected them. 



Bete roits^e X 12c. 



