The Miceoscope. 331 



wash in alcohol for a few minutes, the solution being changed until 

 free from acid; then place for one-half to one minute in an alcoholic 

 solution, yV gr. of picric acid to 3 j ; wash in alcohol, and transferred 

 through absolute alcohol and clove oil to balsam; then finish. 



2. Eosin method. Place the sections in a solution of eosin, one 

 part to 1,000 of water, for a minute or two, then for a very short time 

 in water slightly acidulated with acetic acid; then movmt in glycerine 

 or Canada balsam. I would recommend the Lissotriton punctratus 

 (smooth skin newt) and the Amphiuma tridactylum as the best 

 subjects for the above methods, as the muscular fibers, especially of 

 the tongvie, being particularly beautiful, the transverse striae being 

 very well marked and the nuclei very large in both species, and 

 greatly elongated in Amphiuma, stretching about one-third across 

 the field with a one-fifth objective and A ocular. 



3. Double-straining with indigo carmine and carmine. In 

 this method, if only the operator could be sure of the result, he 

 would have a beautiful and useful stain. The specimens, if hardened 

 in chromic acid, must be deprived of it by washing, and then 

 immersed in the mixed dyes for a quarter of an hour; then trans- 

 feiTed to a saturated solution of oxalic acid, both to "set" the blue 

 color as well as to lighten the general tint; and then, having been 

 washed in the distilled water, mount in C balsam. The stain is 

 made thus: a. A boracic solution of carmine (carmine, 3 ss; borax, 



3 ij ; distilled water, 3 iv). h. A similar solution of indigo- 

 carmine (Carmine 3 ij ; borax 3 ij ; dist. water, ^ iv). Indigo carmine 

 is the trade name for sulphindigotate of potassium, as used by 

 Chrzonozczewsky in his researches upon the commencement of the 

 portal duct. As a general dye, the blue boracic solution of indigo- 

 carmine by itself is good and it stains rapidly. In using the double- 

 staining for vegetable tissue, or even animal, the color is more 

 permanent, I find, if the specimen is immersed in benzine after being 

 in clove oil. In specimens of the liver the portal canal can be seen 

 splendidly; the blood disks in the portal vein are of a brilliant apple- 

 green, the hepatic artery reddish-blue, the process of clisson's capsule 

 blue, or blue-purple; the wall of the portal duct is of the same color, 

 but of a different tint, the columnar cells lining it being just tinted 

 a brownish -purple with blue. In a specimen showing ossifying 

 cartilage the component parts are of various colors and sharply 

 diflferentiated. In ecchymosis of the skin the epithelium, as well as 

 the connective tissue, are colored red, blue, purple, etc., while the 

 extravasated blood cells between the fibers and fat cells are of a 

 vivid green. 



