1 8 8 2 . ] Microscopy. 84 1 



bringing them so much nearer to the British frontier. A large 

 number of the heights are found to be considerably in excess. 

 MICROSCOPY. 1 

 Bibliography of the Microscope. — Mr. Julien Deby, of 

 London, late vice-president of the Belgian Microscopical Society, 

 has commenced the publication, under this title, of a most use- 

 ful work. Part in, relating to the Diatomacea, has appeared, 

 Mr. Frederick Kitton having assisted in its preparation. Parts 1 

 and 11, relating to the microscope proper, the Protozoa, the Des- 

 midiae, etc., will shortly follow. In preparing for his own conve- 

 nience this catalogue of the books and papers in his microscopi- 

 cal library, Mr. Deby has with much labor prepared a catalogue 

 which, with its added desiderata, constitutes a very complete mi- 

 croscopical bibliography. The work includes reference to papers 

 in journals and transactions ; and also contains a chronological 

 index to all the publications referred to. It is handsomely 

 printed for the author, and the necessarily limited edition has 

 been generously distributed by him in the hope of making it use- 

 ful to microscopical friends — a hope which will be abundantly 

 realized. 



Apparent Size of Magnified Objects. — Professor Wm. H. 

 Brewer read a paper upon this subject at the recent meeting of 

 the A. A. A. S. The well known diversity of opinion as to the 

 apparent size of an object under the microscope was illustrated 

 by reports of experiments upon over 400 observers of all classes, 

 ages, occupations and qualifications. The object was a common 

 louse magnified, as estimated by scientific microscopists, to the 

 size of 4.66 inches. By far the greater number of observers 

 underestimated this value; two estimates were only one inch, 

 while seven were over a foot, and one (by an expert draughts- 

 man) was at least five feet. Among new students the first impres- 

 sion was usually somewhat larger than the real value, and this 

 was adhered to for some time. 



Double-staining of nucleated Blood Corpuscles. — Dr. AI- 

 lea Y. Moore gives, in The Microscope, a valuable explanation of 

 the method of differential staining by which his fine slides of 

 blood corpuscles are produced. The blood is spread upon the 

 slide by the usual method, drawing a drop across one slide by 

 means of the edge of another slide. When the film of corpus- 

 cles, thus evenly spread, is thoroughly dry, the slide is flooded 

 for three (3) minutes with a solution of rosin five grains, in dis- 

 tilled water and alcohol, four drachms each. The slide is then 

 washed by passing it gently through clean water, and before dry- 

 mg is flooded for two (2) minutes with a solution of methyl 

 analirre green five grains, in distilled water one ounce. It is then 

 ^his department is edited by. Dr. R. H. Ward, Troy, N. Y. 



