ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 345 



process, commonly used in cotton bleacheries, suggested by Mr. G. 

 Dimmock, obviates the necessity of removing the scales, and leaves 

 the wing perfect. 



The most convenient method for applying the chlorine is as 

 follows : — The wings must first be soaked a few moments in pure 

 alcohol, in order to dissolve out the oily matter in them. If this is 

 not done, the surface of the wings acts as a repellent, and will not be 

 moistened by an aqueous solution. When the wings have become 

 thoroughly soaked by the alcohol, they are ready to be removed to 

 a solution of common bleaching powder. This bleaching powder is 

 sold by druggists as " chloride of lime," but it is really a mixture of 

 calcic hypochlorite, calcic chloride, and calcic hydrate. Ten parts 

 of water dissolve the first two compounds, leaving nearly all the third 

 suspended in the solution. The solution should be made with cold 

 water, filtered, and kept in a tightly corked bottle until required for 

 use. When the wings are transferred to this solution the bleaching 

 commences, and in an hour or two the wings are devoid of markings, 

 although the veins retain a light-brown colour. This is due to the 

 fact that chlorine cannot quite decolorize animal matter, or any sub- 

 stance containing nitrogen, as it does vegetable tissue. 



After the colour has sufficiently disapj)eared from the wings they 

 should be transferred to a wash composed of one part of strong hydro- 

 chloric acid to ten parts of water. And here it may be added that 

 in case the bleaching does not readily commence upon immersion in 

 the bleaching solution, the action may be hastened by a previous 

 dipping in the dilute hydrochloric acid. In the bleaching solution a 

 crust of calcic carbonate, formed by the union of the calcic hydrate 

 of the solution and the carbonic dioxide of the air, is deposited on 

 the wings, and this calcic carbonate the final wash in dilute acid will 

 remove. As soon as the calcic carbonate has disappeared, and all 

 bubbliug, consequent upon its decomposition by the hydrochloric acid, 

 has ceased,' the wings should be well soaked in pure water. They 

 may then be secured on cards with a mucilage of gum tragacanth, or 

 upon glass by the proper transfers, through alcohol and chloroform, 

 to Canada balsam. 



A solution of sodic hydrochlorite, known as " Eau de Labarraque," 

 or a solution of potassic hydrochlorite, known as " Eau de Javelle," 

 when used in place of the solution of bleaching powder, do not leave 

 a deposit of calcic carbonate on the wings, and thus dispense with 

 the wash of dilute acid. A solution of zinc hypochlorite acts more 

 delicately than a solution of sodic hypochlorite, and may be used in 

 place of the latter, as may also solutions of aluminic hypochlorite, or 

 magnesic hypochlorite. 



Modification of Ehrlich's Method for Tubercle Bacilli.* — Dr. G. 



Fiitterer proceeds as follows: — 1. Stain sections after Ehrlich's method. 

 2. Decolorize, in alcohol acidulated with nitric acid (3 drops to a 

 watch-glassful of absolute alcohol), down to a light rose-colour. 3. 

 Immerse for one minute in a well-filtered solution of palladium 



* Virchow's Arch. f. Path. Auat., ci. (1885) p. 198. 



