2 54 Phillips on a Comparative Study of the 



presence of an acid, which fact in itself would show a dififer- 

 ence between granules. This acid would, of course, be neu- 

 tralized by the ammonia, and the granules would therefore 

 stain similarly to others which did not need this neutraliza- 

 tion, and for that reason were different granules. Hierony- 

 mus was able to demonstrate that vacuoles were normally 

 present in the central bodies as well as the peripheral cyto- 

 plasm, and were even found in the end cells of young grow- 

 ing filaments. Though others had found vacuoles in the 

 cytoplasm, Hieronymus was the first to claim them for the 

 nucleus. These vacuoles varied in size from very minute 

 points to more than one-half of the size of the cell, as in 

 Scytonema circinatum and Stigonema ocellatum of Thuret. 

 Palla (60) worked upon a variety of organisms, making 

 very exhaustive experiments. His results may best be given 

 by a translation of his own concluding paragraphs. He 

 says : "These are the results of my investigations thus far : 

 ( I ) The protoplast of the Cyanophycean forms investigated 

 always showed a differentiation into a colorless part, the 

 'central body,' and a colored crust layer, the 'chromato- 

 phore,' outside of which was a colorless ectoplasm, and 

 inside of which, between it and the 'central body,' was a 

 colorless plasmatic layer, the 'plasmaschicht.' (2) In the 

 case of Gloe atrichia pisum, and probably of other Rivulari- 

 acese, there are several 'central bodies' in most cells, and 

 they appear in the most dissimilar formation in the same 

 cell, while the other Cyanophycese have generally only one 

 'central body' in the cells. The central body is homogene- 

 ous and has a structureless membrane surrounding it. It 

 divides by constriction into halves. It is characteristically 

 stained by intra-vitam staining with methyl blue. (3) The 

 chromatophore has a vesiculated structure (webenbau of 

 Biitschli), the coloring matter never appearing uniform, but 

 bound up in numerous small carriers, which are not pure 

 chlorophyll green, but possess the color in which the chroma- 

 tophore appears as a whole. (4) Large vacuoles are a nor- 



