ZOOLOGY AND BOTANY3 MICROSCOPY, ETC. 165 



necessary to remove all the picroearmine from the section ; in fact it is 

 advisable to leave a little adhering to the section, for, within a few days 

 after mounting, the trace of dye left will be absorbed by the section.'] 



Sci.-Gossip, 1884, p. 275. 

 Pedley, p. R. — Stupefying active forms of aquatic life. 



[Advocates the addition of 1-3 per cent, of ordinary soda-water or water 

 charged with carbonic acid gas.] 



Journ. and Froc. Boy. Soc. K S. Wales, XVII. (for 1883) p. 261. 

 Platjt, H. — Farbungs-Methoden zum Nachweis der faulniss-erregenden und 

 pathogenen Mikro-organismen. (Staining methods for demonstrating the 

 saprogenous and pathogenous Micro-organisms.) 



[Gives in a tabular form a summary of all the more important investigation 

 methods for Micro-organisms — j^'^^^'l 



2nd ed., 32 pp., 8vo, Leipzig, 1884. 

 Polycystina, cleaning and mounting. The Microscope, IV. (1884) pp. 280-2. 



Peatt, W. F. — Staining Vegetable Tissues in Picroearmine. 



[Place the sections in alcohol for 1 hour. Immerse in staining solution 

 A-3 hours. Wash in alcohol. Immerse in an alcoholic solution of picrate 

 of ammonia for 1 hour, and for a 2nd hour in a like solution. Place in 

 alcohol and then in oil of cloves for a short time. From Cole's ' Methods 

 of Microscopical Research,' 1884, Part XI.] 



Sci.-Gossip, 1884, p. 276; 1885, p. 18. 

 Reynolds, R. N. — Notes on Microscopic Work. A Rat followed from the 

 Corn-crib to the Microscopist's Cabinet. 16 pp., Detroit, 1884. 



Richard, 0. J. — Instructions pratiques pour la formation et la conservation d'une 

 herbier de Lichens. (Practical instructions for the formation and pre- 

 servation of an herbarium of Lichens.) 2nd ed., 44 pp., 8vo, Paris, 1884. 

 RoYSTON-PiGOTT, G. W. — Notc ou the Structure of the Scales of Butterflies. 



[Contains the following: — "Very much has been written whether the 

 delicate membrane of these beautiful scales is comjDles — I mean double 

 quadruple or single. The question seems settled by the following facts. 

 The sap flows between the tubes ; scales are apparently a kind of 

 flattened hairs, most of which are more or less hollow and similarly 

 endowed with molecules. Squeezed accidentally an oily sap escapes. 

 But another fact of an optical nature is still more decisive. Under the 

 very finest instruments extant the former hazy margin of the most 

 delicate scales becomes brilliantly clear, sharp, and black — a thin black 

 line about the hundred tliousandth part of an inch thick. This sharp 

 black line is as precious an indication of instrumental perfection as the 

 black division is in Saturn's rings to the astronomer. This black line is 

 thus caused. Light is stopped at the edge where the transparent mem- 

 brane is folded back. As an illustration — if gold leaf, which is trans- 

 parent and about 1 /200,000 of an inch thick, be doubled back, at the 

 line of doubling or folding a black line appears in the translucent blue 

 of the leaf. I have seen the same thing on folding carefully a piece of 

 goldbeater's skin. No light shows through at the line of folding. All 

 transparent tubes visible in the best possible instruments show also too 

 black for borders. In the same way each of the ribs of these scales when 

 unclouded with beading or molecules exhibits these beautifully well- 

 defined black lines. Any one who possesses an instrument which clearly 

 and sharply displays these black margins in minute delicate scales may be 

 congratulated on the superlative excellence of his instrument."] 



Engl. Mech., XL. (1884) p. 215. 

 Safftigen, a. 



[Contains " Method of Preparation." Abstr. in ' Amer. Natural.,' XVIII. 

 (1884) p. 1291. Supra, p. 147, and cf. also this Journal, IV. (1884) 

 p. 897.] 



MorpJiol. Jahrbuch, X. (1884) pp. 120-71 (4 pis.). 

 Saunders, W. D. — Microscopic Slide Centeiing. 



[Turn one or more rings in ink with a fine steel pen on the back of the 

 slide.] 



Sci.-Gossip, 1884, p. 276. 



