102 
UPWARD GROWTH OF THE HEAD, AND [Part II. 
from the organisation of all other parts of plants. 
I think that the reason of the death of the beans 
in Dutrochet’s beautiful experiment was, that 
their necks and tap-roots were too far detached 
from the earth to allow them to throw out 
branch-roots; and that, had they thrown out 
branch-roots, they would also have thrown out 
branch-stems . 
If any of the scarlet-runners engaged their 
heads so as to be unable to descend, they broke 
out, like the beans, from the necks. But the 
heads of the gemmules of many scarlet-runners 
came down, grew eight or ten inches horizon¬ 
tally across the wires to the light, and then up 
the side of the pot diagonally to the light, till 
they required support as usual. Some grew 
across the wires without touching them. One 
pressed constantly against the wires, and seemed 
only compelled to its course by the mechanical 
resistance from above. I placed a string for 
each plant to climb, and, as they ascended, I let 
the flower-pot down, so that, at last, it touched 
the floor of the room, and the plants the ceiling. 
They circle round their support against the sun, 
as it is called; that is, the course of their growth 
and of their sap in the half-circle on the south 
side of their supports is from west to east, and in 
the half-circle on the north side of their supports 
