214 



HARDWICKE'S SCIENCE-GOSSIP. 



[Sept. 1, 1867. 



Wanted a Medium.— I have again tried my 

 Land on Deane's Gelatine and Lawrence's Jelly, 

 and Lave again failed. I can't get them as clear as 

 I want them. I used Cox's Gelatine (English) the 

 best I could get here. In the Glycerine Jelly, 

 though made with extreme exactness and care, con- 

 fervoid growths appeared in less than a week in my 

 bottle, though I put it up, sealing as closely as I 

 could. But I made one or two experiments — the 

 most successful of which I will state. When the 

 jelly was as clear as I could get it, I prepared a 

 solution of carbolic acid by shaking up a few drops 

 of the acid with distilled water, and added of this 

 what I thought would flavour the jelly to the dis- 

 taste of animalculee or confervse. This vial has till 

 now been entirely free from any growth or cloudi- 

 ness other than the original impurities, which I 

 have not succeeded in getting out. — E. C. B., Port- 

 land, U. S. 



Cat-Eleas.— In Mr. M'ln tire's article under this 

 title (Science-Gossip i., 278) a figure is given 

 showing the spinous fringe on the under side of the 

 head and on the pro-thorax, which agrees with my 

 own observations of this_ species. In the " Micro- 

 graphic Dictionary," article " Pnlex," the dog-flea 

 is described as the possessor of these appendages, 

 and the head of the cat -flea is referred to as "naked." 

 The figures on Plate 2S correspond to the letter- 

 press. I shall be glad if some gossiper can en- 

 lighten me on this discrepancy. My own specimens 

 were " taken from the life," and I keep no dog. — 

 K Marls. 



Deatii's-Head Moth (Acherontia atropos). — 

 Your correspondent in the August number appears 

 to have some doubt about the pupae of this insect 

 uttering the shrill sound peculiar to the moth, and 

 I also question very much if, during the chrysalis 

 state, it has auy power at all of producing sound. 

 I have had from time to time many pupa?, but never 

 heard the slightest noise from any of them, nor do I 

 remember to have ever heard or read of an instance 

 of pupse producing sound, but, on the other hand, 

 I have several times heard from the moth itself 

 this singular shrill note, and I believe it to be a 

 peculiarity only exhibited by the perfect insect. — 

 T. G. R, Leeds. 



Insect-Sounds. — In books on British moths the 

 Death's Head is said to produce a squeaking noise, 

 and no other instance is given of either moths or 

 butterflies producing a similar sound. I cannot but 

 think this to be an error. In several butterflies I 

 have noticed that when caught they have emitted a 

 sound like that of a blowfly. Having caught a 

 specimen of the small tortoiseshell (Vanessa urticce), 

 on proceeding to nip it near the thorax I was struck 

 by the sound it made, only differing in intensity 

 from that caused by a fly under similar circum- 

 stances. — H. H. 0. Farrell. 



Laev/e in Mushrooms. — Can any of your readers 

 inform me in what manner the larva enters the 

 mushroom? I have frequently noticed immense 

 quantities of these — many half an inch in length, 

 white, with nearly a black head, — and have been 

 much puzzled concerning them, knowing that the 

 food is so short a time coming to perfection. How 

 old can the grub or larva be when it makes its 

 appearance ; and if it has not been feeding in the 

 ground previous to the mushroom showing itself, 

 it must grow with amazing rapidity. — J. B. Waters. 



To Gitow Chara. — Dr. S. would be glad of infor- 

 mation on the proper method of treating Chara and 

 Nitella when grown in aquaria, in order to prevent 

 the growth of Conferva upon them. A large 

 quantity of this is constantly springing up, which 

 he finds is not prevented by keeping a number of 

 water-snails in the glass jars. He has always lost 

 these plants from the same cause. 



Bottom of Aquarium. — As very many marine 

 animals burrow, and as the observation of their pro- 

 ceedings is very interesting, they should be provided 

 with the means of gratifying their inclinations. Eor 

 this purpose a layer of sand should be put on the 

 bottom of the tank, which may vary in depth from 

 one to three inches. If sand from a sea-beach can 

 be readily obtained, it is the most suitable ; but the 

 next best is coarse river sand, such as the Thames 

 sand, commonly sold at the stone-wharves of London 

 for building purposes. It should be well washed 

 until the water runs away clean ; fresh water will 

 do very well for this, but it must be drained off 

 before the sand is put in. What is called silver 

 sand, and the common yellow earthy sand sold in 

 the shops for scouring, are not at all suitable, as 

 they will tinge the water after any amount of wash- 

 ing, the former with lime the latter with ochre. 

 Small pebbles or fine gravel, likewise well washed, 

 may be used to vary the bottom with the sand. 

 Masses of rock, of dimensions suitable to the 

 aquarium, should be put in, to afford shelter and 

 concealment to such animals as like the gloom. To 

 afford this in the highest degree, a flat piece may be 

 set, like a table or cromlech, upon two or three up- 

 right blocks ; or two tall pieces may lean against 

 each other, forming a rude arch, care being taken, 

 whatever arrangement be chosen, that the masses 

 stand with stability. It is of little consequence 

 what sort of rock is selected — limestone, sandstone, 

 granite, conglomerate — but the rougher and the 

 more full of cavities and angles the blocks are, the 

 better will be the effect. — Gosse's Aquarium. 



Hybernation or Birds. — In Jesse's " Gleanings 

 from Natural History" are included some of 

 Gilbert White's, of Seihorne, unpublished papers, 

 in one of which is the passage, "Repeated ac- 

 counts of Swallows, in large numbers, being seen, 

 spring and fall, perched on branches of trees over- 

 hanging the water, induce me greatly to suspect 

 that House Swallows have some strong attachment 

 to water independent of the matter of food ; and 

 that if they do not retire into that element, they 

 conceal themselves in the banks of pools aud rivers 

 during the uncomfortable months of winter." The 

 hybernation of Swallows, either by submersion or 

 concealment in holes and crevices, was a favourite 

 theory of Mr. White's, and a subject that he tried 

 to elucidate, but without success. Had the worthy 

 old naturalist known such a fact as that stated by 

 your correspondent " G. W.," his theory would 

 have been much strengthened. I have myself seen 

 Swallows taken out of the thatched roofs of old 

 cottages, and out of chimneys, in appearance very 

 like those described as taken out of the water near 

 Dantzic ; but in every case they were dead. Erom 

 their appearance, they seemed to have crept into the 

 holes, and become torpid, and then, probably from 

 cold, perished. Is it possible that birds of any 

 kind, even in a torpid state, can exist for a length- 

 ened period under water? The fact related by 

 your correspondent would seem to prove that they 

 can— B. 0. 0. 



