CHEMICAL AND MICROSCOPICAL INVESTIGATIONS. 
19 
colouring-matter of the most powerful and universally extended principles, viz. light, air, and water, when 
supplied to the plant in different degrees of intensity. M. Decaisne thought that he ought not to limit this 
examination to the root of the madder, although it is this specially which is the depository of the colouring- 
matter so important in the arts. “ All the parts of the same vegetable,” he rightly says, “ are tributary 
(‘ solidaires ’) the one to the other in their action, whether growing in the air or in the earth ; and we only 
completely know the action of the one when the others have been carefully studied in their various 
aspects.”*' 
The Plant an Organized Whole. 
This is the conclusion to which I have also been brought— indeed, I might almost say — compelled to 
come ; so that I place no faith in any of the theories of vegetation which isolate the different parts of the 
plant ; but I agree with Kant, in what seems to me a clear definition, that “ the cause of the particular 
mode of existence of a living body resides in the whole” and with Miiller, from whose Physiology t I 
quote, that “ there is in living or organic matter a principle constantly in action the operations of which are 
in accordance with a rational plan, so that the individual parts which it creates in the body are adapted 
to the design of the whole, and this it is which distinguishes organism.” 
I do not hold myself called upon to attempt to define the entity of that living principle or typical 
idea in the plant, of which nevertheless it seems to me to he needful to assume the existence, in order to 
understand the complete contrast which prevails between the totality of the phenomena of organization and 
those of crystallization. 
There are in nature mysteries beyond the domain of science. Investigation fails, and all our study ends 
in this, that the invisible things of the great Artificer, even his eternal power and Godhead, are clearly seen 
by the things that are made. Therefore I consider with an author previously quoted!, that “ Nature and the 
causes and reasons of things, duly contemplated, naturally lead us unto God, and is one way of securing 
our veneration of Him.” I also judge that “We may as well deny what God hath made to be, as what 
he hath spoken to be true, because we understand not how.” I have no knowledge, for instance, how the 
causa causans gives rise to the causa causata, but I am assured that the acknowledgment of the great 
Pirst Cause is essential to our forming any correct notion of secondary causes, or of the “ laws of nature,” 
as we figuratively speak. 
It is, then, to the operation of this principle, which I may call the life of the plant, that I am obliged to 
trace the perfect re-establishment of the bark, with all its complicated parts and functions, over the places from 
which it has been removed by Mr. MTvor’s process. I compared this at first — as, indeed, the first specimens 
sent seemed to justify— to the granulation of flesh over the surface of a wound, hut the accompanying 
drawings under the microscope show the bark in the third time of renewal to be perfectly renewed, as is 
the case in the parts replaced by animals of low organization, as the claw, for instance, is formed again 
after being lost by the lobster. 
The distinguished botanist M. Trecul remarks, “ Not only do the elements of tissues thus denuded give 
rise by successive divisions to new formations, but they also undergo the most remarkable transformations 
to the same end ; so that the woody fibre, the parenchyma of the medullary rays, and even vessels of small 
diameter, become metamorphosed into cellular tissue, the cells of which then become multiplied in their 
turn, and not only so, but this ordinary cellular tissue reproduces in its turn new medullary rays, new 
* The vitality or growing power of plants seems to be pretty equally distributed throughout their entire structure. If 
destitute of any great visible centre of life, almost every portion of them, from the largest stem to the smallest bud, seems 
endowed with the power of establishing independent centres for itself. This potency and general diffusion of life-power enable 
each part of a plant to assist, to act and react upon every other portion ; hence, if the top suffers loss, the roots make haste to 
make it good. In a similar way, if the roots are injured or removed, the top at once ministers to their healing and renewed 
production . — The Gardeners’ Chronicle , July 4 th y 1868. 
j- Yol. i. p. 19. t See Grew^s ‘ Anatomy of Plants/ ii. 79. 
