286 THE EVOLUTION OF LIFE 

to soak therein for twenty minutes, the fluid being 
occasionally shaken, so as to cover the whole in- 
ternal surface of the bottle. The solution is next 
poured out, leaving the surface of the potato and 
the bottle wet with the antiseptic fluid, and the cover 
is tightly screwed on. When this method was em- 
ployed there was never the slightest indication of 
any contamination of the surface of the potato; yet 
after it had been left for a number of weeks in this 
closed and aseptic bottle micro-organisms were often 
found (after careful search) within multitudes of 
closed cells—that is when sections were taken from 
central regions of the potato, but not from peripheral 
portions which had been acted upon by the anti- 
septic fluid. Representatives of such organisms as 
well as of others obtained from the cells of a turnip, 
preserved in such a way as to be absolutely free 
from all chances of external contamination, are to 
be seen in my work “Studies in Heterogenesis,” 
Plate XVILI., Figs. 193-197, and also in “The Nature 
and Origin of Living Matter,” Plate II., Figs. 4, 5, 6. 
In all such cases the micro-organisms seem first to 
show themselves as motionless specks in the prim- 
ordial utricle of the closed cells, and the specks 
develop into such Bacilli as are shown in the 
figures. The fact that the first things to appear 
within the closed cells are mere motionless germs 
suffices of itself to negative the possibility of in- 
fection. Mere motionless germs could not infect. 
Vegetable cells can only be penetrated by adult 
organisms capable of secreting toxins for killing 
the cells, and a cytase for softening their walls. 
