SPECIAL METHODS. 



203 



from a few minutes to several hours, according to the depth 

 of the staining and the character of the preparation. The 

 examination may be made in glycerine. Such preparations 

 keep only a very short time, while very permanent prepara- 

 tions may be made by transferring to Canada balsam even 

 sections stained with iodine green. In this transfer alcohol 

 must be wholly avoided, since it decolorizes the chromato- 

 phores. Phenol and aniline also are not suited for this use. 

 Therefore I simply allowed the sections to dry, after wash- 

 ing them with water, and then treated them with xylol, and 

 finally added xylol-balsam. 



354. For staining with fuchsin^ I have used the ammonia 

 fuchsin mentioned in 271. I let it act only a short time 

 on the sections, until they begin to become red. Then I 

 wash it out with water, and examine the sections in glycer- 

 ine or transfer them in the above described manner, by dry- 

 ing, to balsam. Alcohol decolorizes the chromatophores in 

 this case, also. 



II. The Finer Striicture of the CJiroinatopliores. 



355. Opinions are at present divided as to the intimate 

 structure of the chromatophores (cf. Zimmermann I, 56 and 

 Bredow I, 380, for the early literature). It is only as to the. 



/P i 



pi A 



FIG. 70. I, chromoplasts from the flower of Neottia nidus-avis; p, protern crystalloids ; 

 / pigment-crystals. II, the same, from the root of Daucus Carota. Ill, the same, 

 from the fruit of Sorbus aucuparia. j, starch-grains. After Schimper. 



chromoplasts that it may be regarded as settled that the 

 pigment occurs partly in crystalline, partly in amorphous 

 form. 



356. In the former case, it forms more or less regular 



