238 



THE AMEKICAK MONTHLY 



[December, 



NOTES. 



— We have had occasion recently 

 to examine one of Messrs H. R. Spen- 

 cer & Go's latest y^g-inch " professional " 

 objectives, and we take pleasure in saying 

 that it is one of the best high-power len- 

 ses we have ever seen. In the words of a 

 competent judge its definition is " superb." 

 It is not of veiy great angular aperture, 

 being marked 100'' B. A., but it will readi- 

 ly resolve all the diatoms of the test-plate, 

 while it shows the podura-scale beauti- 

 fully. 



Of wide angle objectives, there are 

 two 1-inch lenses by Mr. Tolles, in this 

 city, which give the finest resolution of A. 

 pellucida that we have ever seen. 



— -We observe signs of growing interest 

 in photographing with the microscope. 

 Frequent inquiries about the best appara- 

 tus to be used, and concerning the practi- 

 cability of photographing with high powers 

 come to us from all parts of the country. 

 We have already referred to the admira- 

 ble arrangement for the purpose devised 

 by the Scovill Manufacturing Company, 

 and we have since learned from Messrs. 

 J. W. Oueen & Co. that they are making, 

 or already have made, preparations to sup- 

 ply complete outfits for photo-microgra- 

 phy. 



— Some " Notes on the Schizomycetes " 

 by W. B. Grover, now being published in 

 Science Gossip are well illustrated, and 

 would prove of interest to many micro- 

 scopists. They are written for the in- 

 formation of those who know nothing 

 about these minute organisms, and the 

 species are clearlv described and compared 

 with each other. 



— O. Biitschli recommends the use of 

 a solution of paraffin in chloroform (satura- 

 ted at 35° C.) for imbedding delicate tis- 

 sues. It possesses great advantages over 

 the turpentine solution. The object to be 

 imbedded is placed in chloroform, then 

 in the solution, kept fluid by warm water, 

 and when permeated by the paraffin, it is 

 placed in a watch-glass with some of the 

 solution and the chloroform driven off by 

 heat. Then it can be imbedded in a lar- 

 ger mass of paraffin in the usual way. 



— The angular aperture discussion bids 

 fair to continue for some time yet in 

 England. A few months ago Mr. George 

 E. Davies wrote " A Plea for Wide Aper- 

 tures," which was a reply to, and an able 

 criticism from a practical point of view, 



of Prof. Abbe's recent article on the 

 " Relation of Aperture and Power in the 

 Microscope." At a meeting of the Man- 

 chester Microscopical Society, held Sep- 

 tember 7th, Mr. J. L. W. Miles read a 

 paper on angular aperture, which has 

 stirred up a real "hornet's nest." Mr. 

 Davies declines to discuss the matter " in 

 its present form," and it bids fair to be- 

 come another warfare of personalities, such 

 as the same subject has led to in the past. 

 We very much fear that Mr. Miles will 

 get the worst of the battle, but he is still 

 confident and eager for the fray, for he 

 proposes to meet his opponents in battle 

 array at another meeting of the same 

 Society. 



— So far as we are aware, no fluid has 

 yet been proposed for homogeneous im- 

 mersion lenses equal to the ol of cedar. 

 The objection to this is its extreme fluid- 

 ity, and substitutes are therefore much 

 used. It has been found that oil of cedar 

 increases in consistency by exposure in 

 thin layers to the air and sun. Its index 

 of refraction is thereby raised to 1'520, 

 but olive or castor oil can be used to bring 

 it back to required index 1-510. 



— The Aulacodiscus Kittoni is one of 

 the beautiful discoid diatoms familiar to 

 microscopists on the Pacific coast, and- 

 very common in cabinets ever3rwhere. 

 This diatom most frequently has four 

 radiating processes, but often six, and ab- 

 normal forms are not rare. The number 

 of rays is not characteristic of the species. 

 Some time ago Rev. J. L. Mills had what 

 he thought was an A. Kittoni with four- 

 teen rays. Mr. F. Kitton, in examining 

 this specimen, discovered that it was com- 

 posed of two valves together, each having 

 seven rays, the elevations of one fitting 

 into the concavities of the other, thus giv- 

 ing the appearance of a single valve with 

 fourteen rays. 



— Mr. J. B. Schnitzler has made some 

 observations on pollen grains, which cer- 

 tainly it would be interesting to repeat. 

 He placed pollen grains of Narcissus 

 poeticiis and Leucojimi cBstivum in the 

 mucilage obtained from the stems of the 

 respective plants, and kept them at a tem- 

 perature of 13 ° C. The pollen-tubes 

 grow rapidly and currents of protoplasm 

 are seen within them. 



— The same author has observed some 



indications that Palmella uvcEformis may, 

 under certain conditions, develop into a 

 filamentous alga resembling Stigeoclo- 



