3°8 
Ishikawa. —Studies on the Embryo Sac 
Some Microchemical Observations on Ovular Tissues. 
Chromatic substance in the chalazal tissue. In the tetrad stage of 
mother-cell, a cell group at the chalazal end, which borders on the base of 
the inner integument, becomes nearly filled with a certain liquid substance 
(Text-fig. XII, 4). The substance accumulates within the cytoplasm, and 
gradually presses the latter against the cell-wall, so much so that the cyto¬ 
plasm is found as a very thin sheet lining the cell-wall and containing a much 
Text-fig. XII. Various stages showing distribution of chromatic substance with reference 
to development of ovule. Hatched part, conducting passage ; darkly shaded part, tissues impreg¬ 
nated with chromatic substance of the first kind; dotted part, those containing substance of the 
second and third kind. All figs, x 140. 
compressed nucleus (Text-fig. XIII). In an advanced st'age (Text-fig. XII, 5), 
the substance in question prevails in the chalazal cells which are situated 
above the end of the conducting passage, and spreads in all directions, 
occupying the main part of the contents of the neighbouring tissues (Text-fig. 
XII, 6, 7). Finally the tissue lying between the conducting passage and the 
embryo sac, and the basal half of the inner layer of the inner integument, 
