SOME STUDIES ON THE GERMINATION OF THE SEED: OF ORYZA SATIVA. 135 
aqueous solution of each component of these mixtures, i.e. osmic acid and 
chromic acid, except acetic acid, is not fatal. Twenty four hours’ steeping, 
which is the usual length of time for fixing ordinary tender tissues, in Flem- 
ming’s mixture without acetic acid (BENDA’s mixture, for example, recom- 
mended for the chondriosome studies, contains no acetic acid) hardly kills the 
embryo of the air-dried rice grains. An aqueous solution of acetic acid 
alone, however, kills the desiccated grains, but an absolute alcoholic and 
ether solution of the same strength are not fatal; many of the grains, even 
when they are cut in half and steeped for 24 hours, have proved capable 
of germination. 
(4) The resistance of the desiccated Oryza grain against toxic solutions 
within a limited length of time is also pronounced even with the grain cut 
in half near the embryo at the endosperm, as in the entire grain. As we 
see in Table IV, many of the desiccated cut grains retained their viability 
after twenty four hours’ steeping in ethyl alcohol, ethyl ether, absolute 
alcoholic solution of resorein, acetic acid, hydroquinone, and naphthalene. In 
the last case, however, only one grain out of ten germinated, whereas none 
of the air-dried whole grain, except in the case of ethyl ether, germinated. 
Regarding the cause of viability opinions among previous authors are 
somewhat diverse. Some consider that the presence of the impermeable 
membrane in the seed coats is the chief factor (Schmp 1901, Drxon 1901), 
but SUKATSCHEFF (1901) doubts this. SUKATSCHEFF finds that the vitality of 
the seed is not destroyed by the action of antiseptics, even when the 
seed-covering is broken; so he thinks, that if the presence of the seed 
coat is the only factor for the resistance of the dormant seed against 
the antiseptics, the explanation is questionable. The findings in the Oryza 
erains also show that the desiccated cut grains are in many cases just as 
resistant as the entire ones. Whole air-dried grains, however, are killed by 
the same treatment, showing that the presence of perfect coating is not the 
only cause of resistance, but that some other factors are at work. We may 
consider at least three possible causes of increased resistance of the desiccat- 
ed seed, namely (1) an increase in the protective action of the selective 
permeable septum, (2) an increase in the filtering power of the endosperm 
tissue, and (3) an increase in the stability of the plasm of the embryo. 
