SPECIAL METHODS 149 



STAINING CILIA 



The cilia of the large spermatogoid of Gingko and the cycads stain 

 beautifully in iron-alum haematoxylin, which not only stains the cilia 

 but even differentiates the free portion from the part between the 

 blepharoplast and the surface. 



The cilia of sperms of Bryophytes and Pteridophytes stain better 

 with gentian violet or crystal violet. The periods are long; not less 

 than 30 minutes, and often several hours will be required. 



The cilia of the motile spores of Thallophytes may often be demon- 

 strated by allowing a drop of the iodine solution used in testing for 

 starch to run under the cover. 



Zimmermann gives the following method: Bring the objects into a 

 drop of water on the slide and invert the drop over the fumes of 1 per 

 cent osmic acid for 5 minutes. Allow the drop to dry. Then add a 

 drop of 20 per cent aqueous solution of tannin, and after 5 minutes 

 wash it off with water. Stain in a strong aqueous solution of fuchsin 

 (or carbol fuchsin) for 5 minutes. Allow the preparation to dry com- 

 pletely, and then add a drop of balsam and a cover. The cilia should 

 take a bright red. 



Zimmermann also found the following method satisfactory for the 

 cilia of the zoospores of algae and fungi : Fix by adding a few drops 

 of 1 per cent osmic acid to the water containing the zoospores; then 

 add an equal amount of a mixture of fuchsin and methyl violet. The 

 fuchsin and methyl violet should be 1 per cent solutions in 95 per cent 

 alcohol. In a few seconds the ciha stain a bright red. 



The brilliant staining of the cilia of motile sperms of cycads with 

 iron-alum haematoxylin would warrant a trial in any other form. 

 Skilfully used, this stain will give good results with almost anything. 



CHONDRIOSOMES 



During the past twenty years the terms chondriosomes, mitochon- 

 dria, Chondriokonten, and about fifty others, have become increasingly 

 frequent in botanical literature. These chondriosomes, although ex- 

 tremely small, can often be seen in living cells. They move as actively 

 as bacteria and very effective moving picture photomicrographs have 

 been made. While probably present in most cells, they are not differ- 

 entiated by the methods usually employed for other purposes. Most 

 of them bear a superficial resemblance to coccus, bacillus, and spirillum 

 forms of bacteria (Fig. 27). 



