212 PROCESS OF DEVELOPEMENT. CHAP. IV. 



to be a reservoir of moisture, proves rather the capa- 

 city inherent in plants of adapting themselves to 

 their situation, by means of an extraordinary exer- 

 tion of their vital energies. 



And Sir J. Sir J. E. Smith professes to hold an intermediate 

 E. Smith. O p m i on between that of Du Hamel, who ascribes to it 

 no peculiar function at all, and that of Linnaeus, who 

 ascribes to it almost every thing important in vege- 

 tation regarding it not as a source of nourishment, 

 but as a reservoir of vital energy or life, analogous 

 to the spinal marrow and nerves in animals, which 

 do not nourish the individual, but give life and 

 vigour to the whole by being diffused throughout 

 the whole of its parts.* But in thus adopting the 

 golden mean, through which, while he guards against 

 ascribing to it too much, he avoids also at the same 

 time the opposite extreme of ascribing to it too little, 

 and steers equally clear both of Charybdis and Scylla, 

 there does not seem to have been much gained in 

 the present instance. The analogy between the 

 pith of vegetables and spinal marrow of animals is 

 not very well made out : if the spinal marrow is 

 injured the parts are immediately paralyzed, and if 

 it is broken the animal dies; but Mr. Knight has 

 shown that a portion of the pith may be abstracted 

 from the shoot so as to effect a disruption of con- 

 tinuity without occasioning any material injury to 

 the plant. It should be recollected, however, in 

 justice to the phytology of ancient Greece, that this 

 * Introduction, p. 40. 



