1882.J 



MICROSCOPICAL jour:n"al. 



19 



should misunderstand such plain lan- 

 guage. 



NOTES. 



— The observations of Dr. Sternberg, 

 described last month on page 227, were 

 made with a i\-inch homogeneous-im- 

 mersion objective, and not by a >^-inch as 

 there stated. 



— The Report of the State Board of 

 Health, of Michigan, for the year ending 

 September 30th, 1880, is a valuable docu- 

 ment. It contains much useful informa- 

 tion for physicians and persons interested 

 in sanitary improvements — there are some 

 good articles on ventilation, the filtration 

 of water, the supply of milk in cities, 

 hygiene, and other important subjects. 

 It is a volume of 500 pages. 



— The Editors of the Botanical Gazette, 

 with the cooperation of Prof. C. P. Barnes, 

 have arranged and published a " Catalogue 

 of the Phzenogamous and Vascular Cryp- 

 togamous Plants of Indiana," which is the 

 first nearly complete list that has been 

 published. It can be obtained from the 

 authors at Crawfordsville, Ind. 



— Perhaps most of our readers are 

 somewhat familiar with the recent investi- 

 gations of Prof. Pringsheim, upon Chloro- 

 phyll, in the course of which he studied 

 the action of strong sunlight upon the 

 coloring matter, and found that the color 

 was thus destroyed. For the prosecution 

 of these researches a microscope was re- 

 quired especially adapted for studying the 

 action of light of great intensity; such 

 a stand was constructed by Schmidt 

 & Hansch, of Berlin, and is fully described 

 in the Zeitschrift fur Instrument en- 

 kunde. This instrument is two or three 

 times larger than the ordinary stands. 

 The plane mirror is 160™™ in diameter ; 

 it receives light from a heliostat, and re- 

 flects it upward through a system of two 

 plano-convex lenses 28°™^ apart. The 

 lower lens ha an aperture of 66™™, and a 

 focus of 98™™, the upper an aperture of 

 48.4™™ and a focus of 35™™. This ar- 

 rangement furnishes an image of the sun 

 0.35™™ in diameter. Beneath the com- 

 bination there is a support for colored 

 fluids or glasses, when monochromatic 

 light is required, or when the heat-rays 

 are to be absorbed. 



Above the condenser, the stage and the 

 body of the microscope are supported on 

 a pillar, both sliding up and down by 



rack and pinion movements. There is 

 also a description of an ingenious cell for 

 studying the effects of different gases, 

 used by Prof. Pringsheim. 



— A book on " Practical Microscopy," 

 by Mr. George E. Davis, F. R. M. S., will 

 soon be issued in England, and from the 

 notice in the Northern Microscopist, of 

 which Mr. Davis is Editor, we have reason 

 to think it will be a very useful book. A 

 fine colored plate in the November num- 

 ber of the Northern Microscopist illus- 

 trates double-stained sections of wood 

 prepared by different processes. This 

 plate was prepared as a frontispiece for 

 the book. 



— The Detroit Evening News says : — 



" In a lawsuit just tried in York county, 

 S. C, a microscopic examination was 

 made of the defendant's hair and cuticle 

 to determine whether she was of pure 

 or mixed blood." 



— Among the microscopic curiosities 

 of the time, should be mentioned a work- 

 ing steam-engine so small that a thimble 

 will cover it. It weighs about 15 grains, 

 the stroke of the piston is ^^ of an inch, 

 and three drops of water suffice for the 

 boiler. It is composed of 140 pieces, 

 fastened together by 52 screws. This is 

 said to be a product of American ingenui- 

 ty and skill — but we have not seen it ! 



MICROSCOPICAL SOCIETIES. 



At a meeting of the Illinois State Micro- 

 scopical Society, Prof. T. J. Burrill re- 

 counted some of his experiments with the 

 poison of the poison-ivy. He took some 

 of the exudation and found it teeming 

 with bacteria, and he questioned whether 

 the poisoning and the bacteria came from 

 the plant or from some other source. He 

 stated that, upon examination of the wash- 

 ings of the leaves, he found the same form, 

 the milky fluid which exuded from the 

 stem contained numbers of them ; and 

 placing some of this upon his arm, led to 

 results of a serious nature. He went on 

 to say that he had found the foregoing 

 facts true with other plants, among which 

 he mentioned the chiccory, buckwheat and 

 dandelion. 



Dr. Curtis described a new half-incq 

 objective made by Gundlach, and owned 

 by Dr. J. Hollist. The objective, it is 

 claimed by the maker, has an angle 100". 

 The back lens of the objective is large, 

 and extends beyond the border of the 



