INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 1029 



acid added with constant stirring. After the corpuscles have settled, 

 as much of the supernatant liquid as possible is poured off, and in its 

 place is put about an equal volume of normal salt solution. The cor- 

 puscles are allowed to settle, the liquid poured off, and another volume 

 of salt solution added. This is continued until the salt solution 

 acquires only a faint yellow tinge. The use of the salt solution is, 

 first, to dilute the blood in order to avoid distortion of the corpuscles, 

 and second, to wash away the picric acid, so that the subsequent 

 staining will be more satisfactory. 



After pouring off the last salt solution, there is put in its place 10 

 cc. of a mixture of five parts of Frey's carmine and ninety-five parts of 

 picrocarmine. The corpuscles will stain in from one to fifteen hours. 

 A drop of the agitated mixture should be examined occasionally, to 

 ascertain when the staining is sufficient. The nucleus should be 

 deep red, and the body of the corpuscle yellow or pinkish. 



When the staining is completed as much stainer as possible should 

 be poured off, and in its place 10 or 15 cc. of acid glycerine (glycerine 

 100 cc, acetic or formic acid 1 cc). This mixture of corpuscles and 

 glycerine may be jilaced in a bottle and used at any time, it being 

 simply necessary to agitate the mixture slightly or to take up some of 

 the sediment with a pipette and mount it precisely as any other 

 glycerine preparation. 



The process consists, therefore, of these five steps : — 



1. The fresh blood is first diluted with about fifty times its volume 

 of normal salt solution. 2. To this diluted blood is added ten times 

 as great a volume of a saturated aqueous solution of picric acid. 3. 

 The picric acid is washed away with normal salt solution. 4. The 

 corpuscles are stained with picrocarmine, or a mixture of this and 

 Frey's carmine. 5. They are preserved in acid glycerine, and may be 

 mounted for the Microscope at any time. 



Preparing and Mounting Wings of Micro-Lepidoptera.*— Mr. 

 C. H. Fernald describes a method by which the wings of the micro- 

 lepidoptera can be prepared so that the venation can be studied under 

 the compound Microscope, in a manner that will leave no doubt of 

 the presence or absence of the faintest vein in the whole wing- 

 structure. 



The removal of the scales by mechanical means he considers un- 

 satisfactory, as also are the methods recommended for bleaching the 

 wings, described by Chambers and Dimmock. Wlicn mounted dry by 

 the latter method, the scales, although bleached, were not sufficiently 

 transparent to show clearly the more obscure parts of the structure, 

 and when mountctd in Canada balsam, the entire wing was rendered 

 so trans2)arent tliat only" the larger veins were visible, and it was found 

 to be extremely difficult to get rid of the air-bubbles, which so readily 

 gather midtir the concave portions of certain minute wings. 



The author's metliod consists in mounting in cold glycerine ; after 

 having been bleached by Dimniock's method (which, for bleaching, is 



♦ 'Am. Mnn. ISIicr. Jour.,' i. (I8S0) p. 172. (Paper read before the Sub- 

 section of Microscopy of the Am. Assoc. Adv. Sci.) 



