SPECIAL METHODS. 21 



water was added to precipitate the cyanin not taken up by 

 the organisms, in granular form. The cilia, as well as the 

 rest of the protoplasm, are colored at first pale blue, but 

 after the addition of water, deep violet. These methods- 

 have given me no favorable results, when used on various 

 algae. 



380. But I have obtained a very deep staining of the cilia 

 in ChlamydomonaSi Pandorina, and Chromophytum by the 

 following method, which is essentially similar to methods- 

 used for staining the cilia of Bacteria (cf. 476). The 

 objects were first fixed in the hanging drop on the slide 

 by the fumes of osmic acid (cf. 308), and then allowed to 

 dry ; then a drop of a 20$ aqueous tannin solution is added, 

 and washed off with water in five minutes or later. The 

 slide is then plunged in a concentrated aqueous solution of 

 fuchsin, * in which it remains a quarter of an hour or longer. 

 The fuchsin solution is now washed off with water, the 

 preparation is again allowed to dry, and finally a drop of 

 balsam and a cover-glass are placed upon it. I have ob- 

 tained in this way very beautiful permanent preparations in 

 which the cilia were stained bright red. 



[I have obtained very satisfactory stainings of the cilia of 

 the zoospores of various algae and fungi by adding to the 

 water containing them a drop or two of a \% solution of 

 osmic acid, and then the same amount of a strong solution 

 in alcohol of equal parts fuchsin and methyl violet. This 

 stains the cilia deep red almost at once ; and the osmic acid 

 need not be removed before adding the stain.] 



9. Protein Grains. 



381. The investigation of the aleurone or protein grains 

 which occur in the seeds of all the higher plants is best con- 

 ducted, in oily seeds, after the removal of the oil, which is 

 often a great hindrance to their study. This may be ac- 



* Carbol-fuchsin ( 468) is especially useful, as it stains deeply in a few- 

 minutes. 



