256 



HARDWICKE'S SCIENCE. GOSSIP. 



its narrow sides, and an ordinary Erench triplet 

 fastened to the other, close against the farthest 

 angle. Arranged with the plano-convex lens directed 

 downward, the axis of the triplet would be hori- 

 zontal, and a horizontal cone of achromatic light 

 would be furnished ; while, by slightly tilting the 

 apparatus, an available and extremely oblique illu- 

 mination would be obtained. 



The Potato Disease. — Dr. Hunt states that 

 the potato disease fungus {Peronospora infestans) 

 destroys the potato starch in the cells of the tuber. 

 Under the microscope he has noticed the general 

 absence of starch in the cells attacked by the 

 Peronospora, although the fact of such invasion 

 being productive of the result described had been 

 denied. 



A New Preservative. — Mr. A. M. Edwards, of 

 Newark, New Jersey, has been successfully engaged 

 in a series of experiments on the properties of 

 salicylic acid as a preservative for microscopical 

 purposes. He has exhibited casts of the uriniferous 

 tubes obtained from Nephritis, which were mounted 

 in a dilute solution in 1874, and are now in as good 

 a condition as when first put up. Volvox globator 

 can be preserved in this solution with equal success. 



Animal Circulation. — Take a young water- 

 snail (Planorbis) on a slide in a shallow cell with 

 water ; apply a strong light under it, and with an 

 inch objective you can see the action of the heart 

 beautifully. I find it better to get old ones. Keep 

 them in a bottle with food till they breed, and then 

 the youngsters, kept in clear water, will have much 

 more transparent shells. — F. Barnard, Kew, Vic- 

 toria. 



"The Microscopy of Starch." — My husband, 

 for pleasure, has worked at the microscope, mount- 

 ing objects, &c, for upwards of fifty years. About 

 twenty years ago he mounted, in balsam, potato 

 flour, tous-les-mois, Bermuda arrowroot, &c. We 

 were looking at these specimens last evening : they 

 are as perfect as ever. " J. C. Thompson " may be 

 interested in the above fact. — F. S. 



ZOOLOGY. 



"The Aquarium, its Inhabitants, Struc- 

 ture, and Management," by J. E. Taylor, 

 E.L.S., &c. — Our position with regard to this book 

 forbids us to do more than announce its publication. 

 It is hoped that all interested in aquaria, public and 

 private, marine and fresh- water, will find it a popular 

 manual. All the animals yet acclimatized are noted, 

 and hints are given for their further domestication. 

 Lovers of nature will, it is hoped, be here provided 

 with instruction how to proceed in everything re- 

 lating to aquaria. The work is illustrated with 



nearly 300 good engravings, and all that re- 

 mains is for us to thank the publisher for intro- 

 ducing it to the public in such an excellent and 

 attractive manner. 



Embryology of the Salpidje.— At the Boston 

 Natural History Society, Dr. W. K. Brooks has 

 made a contribution to the embryology of Salpa, 

 which is startling to naturalists, and will be of 

 great importance if confirmed. He says that in 

 tracing back the history of the zooids composing 

 a'chain, the egg is present at all periods of growth, of 

 exactly the same size and appearance as at the time 

 of its impregnation. He concludes that the animal, 

 which has no existence, cannot be the parent of the 

 egg which is already fully formed. Thus the ex- 

 planation is that the solitary salpa is the female, 

 which produces a chain of males by budding, and 

 discharges an egg into the body of each before 

 birth. These eggs are impregnated while the zooids 

 of the chain are very small and sexually immature, 

 and develop into females, which give rise to other 

 males in the same way. After the foetus has been 

 discharged from the body of the male, the latter 

 attains its full size, becomes sexually mature, and 

 discharges its spermatic fluid into the water, to 

 gain access to the eggs of other immature chains. 

 This arrangement is compared with other cases, 

 as in cirripeds, arachnids, argonaut, in which the 

 male is to some extent parasitic on, or supplemental 

 to, the female. 



The "Popular Science Review " for October 

 contains some excellent articles, noticeable among 

 which is that by the Rev. W. H. Dallinger on 

 '* Practical Notes on Heterogenesis." This will be 

 eagerly read by all who take an interest in the 

 "Origin of Life." Professor TyndalPs paper on 

 "The Parallel Roads of Glen Roy" is another 

 contribution to the already abundant literature 

 on these peculiar geological phenomena. Mr. 

 H. J. Slack has a paper on " Human Personality," 

 and the editor a telling one on the "Vivisection 

 Clamour." In this number the editor, Dr. Henry 

 Lawson, bids- farewell to his readers, after having 

 ably occupied the editorial chair for many years. 

 We understand that his successor is Mr. W. S. 

 Dallas, F.L.S., the Secretary of the Geological 

 Society of London, and one of the first writers 

 on natural science of our time. 



Strange Commensalism. — M. Trecul has re- 

 cently made a singular communication to the Paris 

 Academy of Sciences on the capture of rattlesnakes, 

 and the supposed association of these serpents with 

 a small owl and a small dormouse. When travelling, 

 in 1S48, in the region west of Arkansas, he caught 

 snakes by passing over them, when erect, a loop 

 with running knot attached to his ramrod; they 

 remained quite straight and were easily killed. The 



