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HARDWICKE'S SCIENCE-GOSSIP. 



[Aug. 1, 1867. 



MICROSCOPY. 



Diatomace.e. — It will be interesting to the 

 readers of Science-Gossip to know that Herr 

 Eulenstein of Wurtembergis at present engaged on 

 a complete synopsis of "British and Foreign Dia- 

 tomacepe. It is to consist of five sections, and each 

 section lias to be accompanied by 100 slides of 

 mounted diatoms, each slide being as far as practic- 

 able pure, that is free from intermixture of diatoms, 

 other than those it is intended to illustrate. I 

 believe Herr Eulenstein will be glad to receive 

 communications from any English diatomists, of 

 pure gatherings of either fresh-water or marine 

 diatomacea?, but specially of the latter. — T. P. 

 Barkas, Neiccastle-on-Tyne. 



Mounting Desmids.— The great want which 

 has marred all efforts (to mount desmids success- 

 fully) has been a fitting medium ; a fluid of such a 

 nature that the plant, when immersed in it shall not 

 become distorted, or indeed receive any appreciable 

 change for a long lapse of years, provided the 

 cement inclosing it retains its air-tight properties. 

 The want of success, it must be allowed, has not 

 arisen from the positive evaporation of the liquids 

 employed, but from the method of employing them. 

 Following a natural law, the frustule, immediately 

 upon being inclosed in its cell, begins to part with 

 the water contained within itself. And what is the 

 consequence? The surrounding medium cannot 

 take the place of the water, the primordial utricle 

 contracts, the contents of the cell collapse, and 

 the plant is left as much changed 'and disfigured 

 as though it had been originally dried. The bota- 

 nical world is, therefore, greatly indebted to Herr 

 Hantzsch, of Dresden, for his researches in this 

 direction, which have resulted in discovering an 

 arrangement which completely supersedes the 

 various unsatisfactory plans hitherto adopted. 



[This plan is fully detailed in "Nave's Handy- 

 book to Collection, &c," just published, from which 

 the above remarks are quoted. The old process 

 would occupy too much space to quote entire ; 

 we must therefore refer our readers to the book 

 itself, in which they will find many other useful 

 hints.— Ed.] 



Microscopic Measurement.— At the meeting 

 of the Dublin Microscopical Club (21st of March), 

 Mr. Stoney submitted to the club reasons which 

 appeared to him, in the present state of science, to 

 require the general adoption by scientific men, of 

 the subdivisions of the metre in estimating micro- 

 metrical magnitudes. He observed, too, that all 

 confusion and inconvenience arising from the use of 

 fractions may be avoided by a very simple extension 

 of the nomenclature of the metrical system, which 



he thought himself justified.in recommending to the 

 club, from the assistance he had himself received 

 from it. 



Ciliary Muscle of the Eye.— At the Quekett 

 Microscopical Club (May 21th), Ernest Hart, Esq., 

 President, submitted his reasons for doubting the 

 existence of sphinctral muscles, or circular fibres of 

 ciliary muscle, which could influence the accom- 

 modative action of the eye, and in a very interesting 

 and lucid communication expounded the theories 

 which have been 'propounded, to account for the 

 accommodation of the eye, with the result of his own 

 investigations on the subject. 



The Study of Mosses.— Dr. R. Braithwaite, 

 E.L.S., at the Quekett Microscopical Club (June 26), 

 read a paper on the structure and classification of 

 mosses, during which he gave a succinct account of 

 the structure, growth, and development of these 

 plants, with hints for their collection, preservation, 

 and examination, adding thereto some remarks on 

 the principles adopted in their classification. A 

 large number of mounted preparations, illustrative 

 of the subject, were exhibited under a series of 

 microscopes provided for the purpose. Later in 

 the evening, it was proposed that classes for the 

 study of mosses and microscopic fungi should be 

 organized in the autumn, Dr. Braithwaite and Mr. 

 M. C. Cooke offering to take charge of such classes 

 respectively. 



Otolites. — Mr. Higgins complains of the report 

 of his communication on this subject, published at 

 p. 151 — that he did not read a paper, but com- 

 municated his observations viva voce, hence our 

 report, taken from shorthand notes made for the 

 committee, was not literally correct — that 

 "Otolites" was spelt incorrectly throughout the 

 report. And, finally, he sends us a corrected ac- 

 count, which we fear that we cannot avail ourselves 

 of, in a manner so as to make the errata wholly 

 intelligible to our readers, except by reprinting the 

 entire communication. In line 23, read " though in 

 some members of the Ray family and the Sharks, 

 there is a tubular prolongation of the lining mem- 

 brane, reaching from the otocrane to the external 

 surface of the skull. In almost all other fish, the 

 whole of the auditory organs are contained in the 

 otocrane, which are two deep depressions in the 

 interior of the skull, situated on either side of the 

 brain.'" And at p. 152, line 6, "The sacculus 

 consists of one large sac, containing the central 

 otolite. The ordinary position of the superior otolite 

 is at the junction of the anterior and posterior semi- 

 circular canals, but in two specimens, &c." And at 

 line 16, "From the lower sac, two tubes pass 

 through the base of the skull, communicating by a 

 chain of ossicles with the tube of the anterior air- 

 bladder. These ossicula are the only true, &c." 



