the Developement of the seminal Germ. 257 
The radicle of the grain measured about half an inch in length, 
having descended, like that of the bean, till it passed the 
lower extremity of the tube, though there was no earth in its 
course, and no moisture coming to it but from above. The 
sheath of the plumelet had just begun to project beyond the in- 
teguments of the seed. 
On the 29th of July, at mid-day, the sheath of the plumelet 
or cotyledon of the grain measured a quarter of an inch in 
length, having extended in a straight line, sloping a little down- 
wards, with the point ascending, but not more than just percep- 
tibly so. The main fibre of the root measured an inch and a half 
in length, and the two lateral fibres about an inch each, having 
assumed now a direction rather horizontal, and along the under 
surface of the earth of the tube, with the point also ascending. 
— The radicle of the bean had increased much in thickness, and 
sent out lateral and descending fibres. But the main or tap root 
had assumed a horizontal direction at the lower extremity, in the 
manner of the fibres issuing from the grain. At ten o'clock at 
night the cotyledon of the grain measured nearly half an inch 
in length, and was evidently bent upwards at the point, forcing 
its way through the earth, and ascending by the side of the — 
so that its progress was very easily traced. 
On the 30th of July the cotyledon of the grain had dessiné 
somewhat in the night, and in the ascending direction it had 
assumed the day before, being quite. half an inch in length. 
The plumelet of the bean had not yet escaped from within the 
lobes of the cotyledon, owing, I suppose, to the confined situa- ` 
tion in which the seed was placed within the tube, as well as to 
the want of due nourishment, arising from the circumstance of 
the root's being now almost wholly below the earth. Indeed the 
germination both of the bean and grain was much less rapid and 
vigorous 
