254 Phillips on a Comparative Study of the 
presence of an acid, which fact in itself would show a differ- 
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: 
(1) 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 Gloeotrichia pisum, and probably of other Rivulari- 
acez, there are several ‘central bodies’ in most cells, and 
they appear in the most dissimilar formation in the same 
cell, while the other Cyanophycez 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 
Butschli), 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- 
