IRON COMPOUNDS IN ANIMAL AND VEGETABLE CELLS. 267 
few in number, and the conditions which greatly influence the 
number of the “cyanophycin” granules have apparently no 
effect upon them. In Oscillaria Froelichii a filament may 
contain large numbers of both elements, another may contain 
“ eyanophycin” granules only, while a third may be free from 
the latter but contain a large number of vesicles, and all in 
the same preparation. In Cylindrospermum majus the 
“cyanophycin” granules of the spore diminish somewhat in 
number and volume during the formation of the episporium, 
and in the spore which is undergoing its initial division their 
number is very greatly reduced, the central body appearing at 
the same time increased in volume. 
4, In the heterocysts of Nostoc commune, Cylindro- 
spermum majus, and Scytonemasp., picro-carmine demon- 
strates the presence of “‘ cyanophycin”’ substance in a button- 
shaped body at one or both ends of the cell, according as the 
heterocyst is terminal or intercalary. A strand of ‘ cyano- 
phycin” connects this body with the contents of the neigh- 
bouring cell. In the heterocyst the ‘‘ cyanophycin” body is 
quite unconnected with the homogeneous cytoplasm which occu- 
pies the remainder of the cavity, and stains but faintly with 
hematoxylin and not at all with picro-carmine. When sub- 
jected to the prolonged action of the glycerine and sulphide 
mixture the “cyanophycin,” both of the button and of the 
strand, gave a deep reaction for iron, and a feebler reaction 
was obtained in the cytoplasm (fig. 8). 
It thus appears that in the Cyanophycee there is a substance, 
containing ‘ masked ”’ iron, in many respects like the chromatin 
of more highly organized cells, and that the ‘ cyanophycin,” 
a compound of undetermined nature, may, in some forms at 
least, also give evidence of the presence of the element in a 
firmly combined condition. 
1 This connection has already been described by Hansgirg, ‘ Physiologische 
und Alyologische Studien,’ Prague, 1887, pp. 125, 126. The description is 
quoted in full by Deinega. 
