FECUNDATION. 181 
and the pollen tube are here still more enlarged, the better to show 
the structure and passage of the tube through the substance of 
stigma. 
In order to understand this curious organic peculiarity, Fig. 275 
Fig. 274.—Conducting Tissue in Datura Magnified. 
represents a similar stigma of the Datwra seen externally, and 
resembling, as M. Brongniart says, a pincushion full of pins. But 
such is the incessant progress of science, that in our days these 
early observations of M. A. Brongniart have been carried much 
further, and recent investigations show still more clearly the 
System of progression in the pollen-tube. 
This tube, as M. Brongniart has shown, elongates itself by 
& most remarkable vegetative process, insinuating itself into the 
interstices of the cellular tissue, which has been designated from 
this cause the conducting tissue, and that doubtless by which it is 
