1882.J 



MICKOSCOPICAL JOUKNAL. 



99 



NOTES. 



— In the Popular Science Monthly, of 

 April, there is an interesting sketch of 

 M. Louis Pasteur, with a portrait of that 

 distinguished investigator. Pasteur is a 

 man whose name will always be closely 

 associated with investigations of ferments, 

 and the organisms connected with disease. 

 He is an excellent chemist as well as a 

 close observer with the microscope. Few 

 men, indeed, have worked so earnestly in 

 science as Pasteur, and few have lived to 

 see the results of their labor so widely ap- 

 preciated. 



— Messrs. J. W. Queen & Co. have a 

 series of twenty-four sections of starch- 

 bearing vegetables and starch-granules 

 which they recommend as polariscope 

 objects. We should think they would be 

 very attractive objects, for a section of a 

 potato mounted for the polariscope is very 

 gorgeous. We do not know the price of 

 the set, and we have not seen the slides, 

 but they are probably well mounted. 



— Mr. W. H. Bulloch claims to have been 

 the first to introduce an iris diaphragm 

 fitted with the society-screw for use above 

 an objective. In his catalogue of 1878, 

 page 8, he refers to this sentence : " The 

 Iris Diaphragm has the society-screw so 

 that any objective can be used for con- 

 denser, or it can be used above the ob- 

 jective as an adapter, to reduce the 

 angle of light in the instrument." He 

 caims priority of invention on the ground 

 of having been the first to publish a 

 description of it. 



— Mr. E. S. Nott writes that he found 

 last month Aviphipleura pellucida in a 

 small brook at Hamburg, in Erie County, 

 New York State. He states that it is 

 smaller than those of Moller in the ratio 

 of 12 to 16, and the lines are correspond- 

 ingly finer. 



— Rev. J. J. Halley, of Melbourne, 

 Australia, recently adressed the Royal 

 Microscopical Society of London, describ- 

 ing a process of preparing wax cells that 

 had proved to be durable. 



A mixture of wax and spermaceti 

 (about Yd part of the latter) is placed 

 upon the middle of the slide, and the 

 surface made perfectly level. The slide 

 is then placed on the turn-table and the 

 cell turned up out of the solid wax. 



— Dr. J. Muller, of the University of 

 Geneva, has made some observations 

 upon a lichen, Coenogonium pannosum, 



which bear strongly against Schwende- 

 ner's hypothesis. He finds in this species 

 that the filament which contains the 

 gonidia, and which, if the lichen is an 

 alga with a parasitic fungus, would be the 

 algal filament, suddenly narrows from a 

 diameter of 8/>« to only 2/^. The narrowed 

 filament corresponds with the so-called 

 fungus-hypha of other lichens, but a very 

 careful examination shows that it contains 

 micro-gonidia, and is not a fungus- 

 filament. A translation of this article is 

 published in Grevillea, of March, 



CORRESPONDENCE. 



On Amphipleura Pellucida. 



To THE Editor: — American micro- 

 scopists can, with a few exceptions, be di- 

 vided into two classes, namely, those who 

 test objectives and demand wider angle 

 for them, and those who are laboring for 

 the improvement of microscope-stands. 

 In the second mentioned class are those 

 who are trying to pursuade makers of the 

 instrument to adopt uniform names and 

 sizes for accessories to the microsco|)e. 

 Belonging to both classes are those who 

 desire that the metric system of measure- 

 ment shall be used in microscopical work. 

 I belong to the first named class, ranking 

 in ability next to the lowest man. For en- 

 larging our knowledge of microscopical 

 natural history, we Americans rely mainly 

 on observations abroad. 



An American, experienced in using the 

 microscope, who succeeded with an ob- 

 jective, theoretically competent, in show- 

 ing the lines on Amphipleura pellucida 

 — the first " resolution " of those lines ever 

 made, perhaps, — subsequently found that 

 at the time of such first "resolution," he 

 had been for eighteen months the possesser 

 of another objective, by a different maker, 

 less capable, theoretically, which accom- 

 plished the same result. This was unfortun- 

 ate for the maker of the older object-glass, 

 who was an unpretending man, because 

 he had, as thus related, constructed, but 

 was never publicly credited with con- 

 structing, the first objective which showed 

 these fine markings ; and it was unfortun- 

 ate for the microscopist, also, because 

 practical investigation might have saved 

 him eighteen months of time spent in 

 theorizing. 



Inexpressibly sad was the fate of an- 

 other American microscopist who lived 

 before the time of immersion-objectives. 

 He was a searcher for diatom markings — 



