i84 



HARDWICKE'S SCIENCE-GOSSIP. 



MICROSCOPY. 



The Highbury Microscopical and Scientific 

 Society closed its sixth session on Thursday, the 

 9th of June, with a conversazione at Harecourt Hall. 

 It was numerously attended. Amongst the objects 

 exhibited the marvellously-arranged diatoms of Dr. 

 Dempsey, and the anatomical preparations of Mr. 

 Herbert Williamson, were particularly noteworthy. 



Mounting Vessels, «S:c. — In reply to your corre- 

 spondent " Beginner," I may state that I have found 

 the following process for separating spiral, scalari- 

 form, and annular vessels, answer admirably. Cut 

 about an inch of the stem containing any one of these 

 vessels, and immerse it in solution of potash for two 

 days, then wash well in water, and digest in very 

 dilute hydrochloric acid, so as to get rid of all the 

 alkah ; then put the softened stem between two glasses 

 and disintegrate it by pressure ; it will then yield a 

 soft mass of pulp ; this should be stirred up in a glass 

 of clear water, when the vessels will be seen floating 

 about like threads, and can be easily picked out with 

 a hooked needle. I find it best to stain them with 

 anilin and mount in balsam. Spiral vessels may be 

 found in the petiole of the Pelargonium, annular 

 vessels in that of the rhubarb, and scalariform in the 

 stipe of the brake fern. Maceration for a short time 

 in alkali will destroy almost any parenchymatous 

 structure, leaving the prosenchyma and vascular 

 tissue untouched. Wood- cells are not so easy to 

 isolate, but may be admirably seen in a longitudinal 

 section of a piece of deal. I am sorry I cannot 

 help "Beginner" as to Dcutzia scahra, for I have 

 never tried to mount that object. I always obtain 

 mounts of stellate hairs from Malvse and Altnese 

 by shaving them off with a sharp razor. The exotic 

 itxx\. Nephoboliis pertusits gxsti, an exquisitely beautiful 

 stellate hair.— 7. O. B. 



Ceratophyllum. — I have found another of those 

 peculiar- formed Ceratophylhiin or " Skeleton Wheel- 

 bearer," in the same pond as I found the one reported 

 by me and figured in the May number of Science- 

 Gossip. This tends to prove my idea that it is 

 another species of the genus Ceratophyllum. — T. B, 

 Rosseter, 



"The Fungoid Origin of Epidemics." — This 

 is the title of a lecture delivered before the Keswick 

 Literary and Scientific Society by M. W. Taylor, M.D. 

 It is a very thoughtful and condensed epitome of the 

 germ theory of disease, and so far is a useful 

 pamphlet for students. In it such would find all the 

 stock arguments in favour of this theory. We judge 

 from its perusal that Dr. Taylor is quite unacquainted 

 with Dr. Drysdale's address on this subject, delivered 

 before the Literary and Philosophical Society of 

 Liverpool, about a couple of years ago, and after- 

 wards pubhshed as a shilling pamphlet. After reading 



that we think so highly of Dr. Taylor as to believe he 

 would alter many of his opinions as to the fungoid 

 origin of some epidemics, if not all. 



"The Micrographic Dictionary " (London : 

 Van Voorst). We are glad to welcome the reappear- 

 ance of an old and trusted friend, in the shape of 

 Part I. 4th ed. of this invaluable work. It is being 

 issued, revised and corrected, in half-crown monthly 

 parts. 



ZOOLOGY. 



Rat's Nest. Black Rats. — As the present distri- 

 bution of Mus rattiis in Great Britain is a matter 

 of interest to zoologists, will Mr. J. Senel kindly 

 inform us the locality of the farm premises in which 

 he finds this species more common than Mus decti- 



maiuts . 



-T.S. 



Buffon's Skua. — A specimen oi Lestrea Bn^onii 

 was captured at Tuxford and kept a fortnight, but 

 on Tuesday last, having apparently recovered its 

 health and strength, it flew away. One wing was 

 cut, so that it will probably be recaptured. Mr. 

 John N. Dufty, of the Grammar School, will be glad 

 to hear of it, or will give particulars to inquiring 

 naturalists. Morris mentions eight occurrences in 

 England, and Atkinson says " this skua can only be 

 considered a rare and accidental visitor." I believe 

 this is the first recorded instance in Notts. — yokn 

 N. Dufty, F.G.S. 



Parasites on Hydra fusca. — It would be 

 interesting to learn upon what evidence the editors 

 of the Micrographic Dictionary based their opinion 

 that the presence of parasites on //. fusca indicated 

 failing health ; and, also, what they would consider 

 to be infallible signs of perfect health in H. fusca, 

 and kindred organisms. I have frequently obtained 

 these zoophytes from the canal running through 

 Preston ; but in no instance have I seen them free 

 from parasitic life, Trichodina pcdiculus being always 

 present. Yet the Hydra never appeared the least 

 inconvenienced by them, but went about its business 

 with the most apparent unconcern, contracting and 

 expanding its tentacles in a most lively manner. If 

 the presence of parasites really indicates lack of 

 health, then disease is the rule, and health the ex- 

 ception ; not alone in the microscopical world, but 

 also in the higher, yea, even in the highest orders 

 of nature. — F. J. George. 



Pea-green Moth (To)-trix viridana). — The oak- 

 trees in this neighbourhood have suffered very much 

 from the ravages of the larvae of this moth, being in 

 many places entirely stripped of their foliage, there- 

 by giving a strangely wintry aspect to the landscape. 

 During May the caterpillars suspended themselves by 

 fine silken threads from the branches and proved 



