Journal of Applied Microscopy. 



611 



borax, and ammonium carmines come under this head, and are prepared by 

 boiUng carmine in certain per cent, sokitions of the basic or neutral substances. 

 These are not very vigorous stains and those strongly alkaline are liable to 

 macerate the tissue. 



Alcoholic Mixtures. — Ordinary borax carmine (Grenacher's), which has 

 been reduced by boiling, is completed in volume by a seventy per cent, alcohol. 

 This makes a stain of good penetration and avoids maceration or treatment 

 with aqueous solutions. It can also be washed out with acid alcohol and left as a 

 pure nuclear stain. Hydrocloric acid carmine (4 g. carmine, 15 cc. of water, 30 

 drops HCl.) is boiled to concentrate, and 95 cc. of eighty-five per cent, alcohol 

 is added. This is filtered hot, neutralized with ammonia till a precipitate 

 appears, and finally filtered. Chloral carmine is made by adding a few grains of 

 chloral hydrate. 



Mixtures for Double Staining. — Picric acid or some of its salts are 

 chiefly used for double staining, either with or after the other stain. The well 

 known picro-carmine is a most variable mixture of picric acid, ammonia, or sodium, 

 or lithium, carbonic acid, also sometime acetic acid and carmine. Picro-car- 

 mine contains only a little free ammonia, and enough ammonium carmine to give 

 a good double stain. The result is just as well or better gained by first staining 

 with borax or para-carmine, and afterwards with picric acid in alcohol or 

 benzol, etc. Indigo-carmine and carmalum or hoemalum give a blue stain to 

 plasma in balsam, after borax-carmine, which gives the nuclear stain. Among 

 other counter stains, Lyons blue can be 

 most successfully used ; it brings out 

 differentially cytoplasmic structures, as 

 the cell body and formative yolk in 

 developing eggs. a. m. c. 



Eternod, Dr. Prof., A. C. F. Instraments et 

 precedes micrographiques nouveaux. Zeit. 

 f. wiss. Mikr. IS: 417-427, 6 figs. 1899. 



This describes a new mechanical 

 stage, an adaptation of Greenough's bin- 

 ocular for use on an ordinary micros- 

 cope, apparatus for squaring paraffin 

 blocks, and a model for mounting sec- 

 tions. 



The instrument for squaring paraffin 

 blocks to be cut in serial sections, or for 

 reconstructions, is shown in Fig. 1, Its 

 principal parts are a vertically-moving 

 knife-carrier (A), a knife (B), a carrier 

 (C), moved horizontally by a special ad- 

 justment screw (D), and surmounted by a 

 support for the paraffin holder, and a 

 plate mounted upon a graduated disc 

 (F) with a pivot, for measuring the angle fig. 1 



•^k/ 



