ANP THE STRUCTURE OF PLANTS. 7§ 



leave the extreme cases to be determined by the chemical components 

 eliminated on their decomposition. And under this broad view of the 

 subject I now proceed to observe, that while they agree in an origin by 

 generation, a growth by nutrition, and a termination by death ; in an 

 organized structure, and an internal hving principle ; they differ in the 

 powers with which the living principle is endowed, and the effects it is 

 capable of exerting. In the plant it is limited, so far as we are capable 

 of tracing it, to the properties of irritabihty, contractility, and simple in- 

 stincts ; in the animal it superadds to these properties those of muscularity, 

 sensation, and voluntary motion. 



There have been, indeed, and there still are, physiologists who, — not 

 adverting to the extraordinary effects which the power of irritability is 

 capable of producing when roused by different stimulants, and under the 

 influence of an internal and all-pervading principle of life, operating by 

 instinctive laws and instinctive actions, or those, as we shall show here- 

 after, which are specially directed to the growth, preservation, or repro- 

 duction of a living frame, or any particular part of it, — have conceived 

 plants as well as animals to be possessed of sensation and muscular fibres ; 

 and as sensation is the result of a particular organ, and the organ pro- 

 ducing it is connected with various others, have at the same time liberally en- 

 dowed them with a brain, a heart, and a stomach ; and have very obligingly 

 permitted them to possess ideas, and the means of communicating ideas ; 

 to fall in love and to marry, and thus far to exercise the distinctive faculty 

 of volition. The whole of which, however, is mere fancy, grounded alto- 

 gether upon an erroneous and contracted view of the effects of the principle 

 of irritability when powerfully excited by the influence of light, heat, air, 

 moisture, and other causes. 



In reality, such kinds of loves and intermarriages are not peculiar to 

 plants, but are common to all nature : they exist between atom and atom, 

 and the philosopher calls them attractions ; they exist between congeries 

 and congeries, and the chemist calls them affinities ; they exist between 

 the iron and the loadstone, and every one denominates them magnetism. 

 Nor let it be said that in these cases of mutual union we have nothing 

 more than a mere aggregation of body ; for we have often a third sub- 

 stance produced, and actually generated, as the result of such union, far 

 more discrepant from the parent substances both in quality and feature 

 than are ever to be met with in vegetable or animal life. Thus if an acid 

 be married to an alkali, the progeny brought forth will be a neutral salt, 

 possessing not the remotest resemblance to the virtues of either of its pa- 

 rents. In like manner if alkohol be married to any of the more powerful 

 acids, and the banns be solemnized over an altar of fire, but not otherwise, 

 the offspring engendered will be a substance called ether, equally unlike 

 both its parents in its disposition. But the form or features are as fre- 

 quently changed as the temper. Thus, if we unite olive oil, which is a 

 liquid, with some of the oxydes of lead, winch are powders, the result is 

 neither a liquid nor a powder, nor a medium of the two, which would be 

 a paste, but the hard adhesive plaster usually called diachylon. So, again, 

 if muriatic acid, which is a liquid, sport in dalliance with the volatile 

 nymph ammonia, which is an invisible gas, the fruit of their embraces will 

 be still more extraordinary in point of form, for the gas and the liquid will 

 engender that solid substance commonly known by the name of sal am- 

 moniac, or, in the new nomenclature, muriate of ammonia. In like manner 

 our common emelling salts, or carbonate of ammonia, though a hard con- 



