OTHER STAINS AND COMBINATIONS. 263 



In either case the stain is an excellent one. The chroma- 

 tin stain is frequently as fine as any that I know of, except 

 that of iron-hrematoxylin, resting and dividing nuclei being 

 differentiated just as in the best chromatin stains. 



If a plasma stain has been obtained, it is generally a very 

 good one, the cytoplasmic reticulum being well brought out, 

 and spindle-relics, Nebenkerne, and other enclosures being 

 very well stained. It may be well, if a good plasma stain 

 has been obtained., to after-stain for twenty-four hours with 

 safranin, followed by differentiation in either neutral or acid 

 alcohol, and clove oil. This gives a fine double-stain, 

 chromatin and nucleoli being of a dark, somewhat brownish 

 red, the plasma purple-grey. The stain is perfectly per- 

 manent in balsam. 



I most highly recommend this stain, which is safe, easy 

 to carry out, and applicable to the study of very various 

 tissues. 



The stain is stated to be a good one for preparations that 

 it is desired to photograph. 



366. Brazilin, the colouring matter of Brazilian redwood or Pernam- 

 buco wood, lias been recommended by EISEX (Zeit. f. wiss. Mik., xiv, 1897, 

 p. 198). MAYER (Grundzuge, p. 203) finds that it gives a stain siinilai- to 

 that of haematein, but much weaker, and is therefore at the least super- 

 fluous. 



367. Orchella (Orseille) (WEDL, Arch. f. path. Anal., Ixxiv, p. 143 ; 

 Journ. Hoy. Mic. Soc., ii, 1879) : for an account of this substance vide 

 COOLEY'S Cyclopaedia, sub voce " Archil ; " and see FOL, Lehrb., p. 192, 

 and former editions of this work. 



368. Orcein (ISRAEL, Virchow's Archiv, cv, 1886, p. 169 ; Journ. Roy. 

 Mic. Soc., 1887, p. 514, and ISRAEL, Prakticum der path. Hist., 2 Aun 1 ., 

 Berlin, 1893, p. 72). Orcein is a dye obtained from the tinctorial lichen, 

 Lecanora parella, and is not to be confused with orcin, another deriva- 

 tive of the same lichen. It is said to unite in itself the staining properties 

 of the basic and acid stains, and also the combination of two contrast 

 colours. Israel stains sections in a solution containing 2 grins, of orcein, 

 2 grins of glacial acetic acid, and 100 c.c. of distilled water, washes in 

 distilled water, and passes rapidly through absolute alcohol to thick cedar 

 oil, in which the preparations remain definitively mounted. Nuclei blue, 

 protoplasm red. 



For the specific staining of elastic and connective tissue by means of this 

 reagent see the paragraphs on the "Connective Tissues" in Part II. 



