176 



BOTANY 



the vacuolar contents in the meanwhile staining slightly, or not 

 at all. It was thought that the vacuoles in the meristematic regions 

 arose by the hydration and swelling of numerous small mito- 

 chondria-like bodies containing a thick solution of metachromatin. 

 As the cells of these regions proceed to differentiate, these cor- 

 puscles swell into small round vacuoles, which eventually fuse into 

 a single large vacuole. 



Guilliermond claimed to have confirmed these results for the 

 yeasts and various ascomycetes (Penicillium, Endomyces Magnusii, 

 and others). Neutral red was found to be the best stain, and gave 



very much clearer 

 results than cresyl 

 blue. This w^orker 

 came to the conclu- 

 sion that in the 

 majority of the fungi 

 the vacuome origi- 





.^^^^B^ms^^M 



%. 



M'*' 





••. 



Fig. 69. — Hyphae of SaproJegnia stained with 

 neutral red. The vacuome shows as a 

 network in the three upper figures, whilst 

 in the lowest it can be seen as a vacuolar 

 canal in which the neutral red has thrown 

 down deeply staining corpuscles. (After 

 Guilliermond, Amer. J. Bot.) 



nated at the hyphal 

 tips as small grains, 

 which showed at 

 first a very uniform 

 staining with neutral 

 red. Further away 

 from the tips these 

 grains began to swell 

 and gradually formed minute vacuoles, in each of which meta- 

 chromatin was precipitated by the neutral red as a small red grain 

 which exhibited marked Brownian movement. In the older hyphae 

 these vacuoles fuse to form larger vacuoles, in which the meta- 

 chromatin particles may be numerous. It was only in the cases 

 of Saprolegnia and Mucor that the filiform and reticulate vacuoles 

 described by Dangeard were discovered. Guilliermond was of the 

 opinion that the vacuome was absolutely distinct from the chondrio- 

 some, for the vacuome absorbs intravitam dyes more quickly, 

 while, on the other hand, the chondriosome is stained neither by 

 cresyl blue nor by neutral red. Apparently in the meristematic 

 regions of the higher plants the colloidal matter in the vacuoles is 



