GOETHE ON THE METAMORPHOSIS OF PLANTS, 7 
but it is not so obvious in plants whose centre is either hollow through- 
out, or filled with pith, or cellular tissue. The supposed important 
functions of the pith being now, on good ground, called in question ; 
and the impulsive and productive power once claimed for it unhesi- 
tatingly attributed to the inner side of the second bark (the so-called 
pulp),* we can more easily understand that whilst an upper node arises 
from the previous one, and receives the sap by means of it (receives it 
too in a more elaborated condition from the intervening operation of 
the leaves), it must not only attain to a more perfect state itself, but 
must consequently transmit a more elaborated sap to its own leaves 
and buds. 
28. Whilst, therefore, the less pure fluids are got rid of, purer ones 
are introduced; and the plant having been gradually brought into a 
more perfect condition, attains the end prescribed to it by nature. We 
see the leaves at length perfectly developed in size and form, and soon 
become aware of a fresh phenomenon, which tells us that the period we 
have been observing has reached its termination, and that a new one is 
approaching ; that, namely, of the Flower. 
III. Transition to the Flowering-period, 
29. The transition to the period at which the flower appears, takes 
place with greater or less rapidity. In the latter case the stem-leaves 
generally become gradually smaller and less divided, whilst increasing 
more or less in width at their base;t at the same time the space be- 
tween the nodes of the stem, if not perceptibly lengthened, becomes at 
least more slender and more delicately formed. 
. 90. It has been observed that if a plant is supplied with copious 
nourishment, the flowering-period is delayed; but that moderate or 
even scanty nourishment accelerates it.t The function of the stem- 
leaves is thus clearly shown, As long as there are crude juices to be 
carried off, the plant must be provided with organs competent to ef- 
fect the task. If superfluous nourishment is foreed on the plant, this 
task must be continued, and flowering becomes almost impossible. 
But, on the other hand, if nourishment is withheld, that operation of 
* The formative tissue between the wood and the bark of an exogenous tree is 
now called cambium: there is gra most active, manifesting itself in the forma- 
tion of wood on the one side, of bark on the other; therein are the channels by which 
the elaborated sap mostly passes in its descent. 
+ See the Plate, Fig. 1. 
$ Wol, ‘ Theoria Generationis, 1759; Linn. Prolepsis, §§ iii. and x. 
H 





