so 



ON ORGANIZED BODIES, 



Tcrete crystallization, are the mere result of the union of two invisible gases^ 

 ammonia and carbonic acid gas, or fixed air ; and which, having duly 

 paid their court to each other, give birth to this solid substance. 



But in all this it may be said that we have no instance of a multiplication 

 of species ; nor in reality of any thing more than the production of a third 

 substance, issuing, like the fabled phoenix of antiquity, out of the ashes or 

 decomposition of the parent stock ; yet in many cases we have instances 

 of multiplication also — and instances far more extraordinary and far 

 more prolific than are ever to be found in the multiplication of either ani- g 

 mals or vegetables. Such especially, are those wonderful increases that f 

 occur in the case of ferments and of contagions. A few particles of yeast 

 lying dormant in a dessert-spoon are introduced into a barrel of beer, or of 

 any other fermentable fluid, and in a few hours propagate their kind through 

 the largest vessel that was ever manufactured ; so that at length every 

 particle of the fluid is converted into a substance of their own nature. 

 A few pestilential miasms are thrown forth from a stagnant marsh or a 

 foul prison, and give birth instantaneously to myriads and myriads of 

 the same species of particles, till the atmosphere becomes impregnated 

 with them through a range of many miles in diameter. Two or three 

 particles of the matter of plague are packed up in a bag of cotton at 

 Aleppo, and are many months afterwards set at liberty in Great Britain* 

 Aided by the stimulus of the air, they instantly set to work, and procreate 

 so rapidly that the whole country in less than a week is laid prostrate by the 

 enormity of their increase. 



Now the terms loves and marriages will just as well apply to all these 

 as to the vegetable creation. The cause of the respective unions, and of 

 the changes that take place in consequence of such unions, are in both 

 cases nothing more than elective attractions : in the mineral and gaseous 

 kingdoms produced by what chemists have denominated the principle of 

 affinity^ and in the vegetable by what physiologists have called the principle 

 of irritability; a principle far nicer and nobler and more delicate than that 

 of afl[inity, and under the influence of an internal, an all-pervading and 

 identifying vital power, capable, as differently excited by diflferent stimu- 

 lants, of producing far nicer and nobler, more delicate and more compli- 

 cated eflfects ; but which in itself is not more diflferent from the principle 



No experiment or observation has hitherto proved vegetables to be pos- 

 sessed of any higher powers than those of irritability, contractility, and those 

 instinctive energies which we shall hereafter show are dependent upon the 

 principle of life. 



It is almost superfluous to observe, in this place, that there are also 

 powers and faculties of a much higher character than any I have yet noticed, 

 appertaining to the nobler ranks of animals ; for at present I am only 

 pointing out the leading characters by which animals in general may be 

 distinguished from vegetables in general, and shall have suflficient oppor- 

 tunities, as we proceed, of adverting to these additional faculties, and of 

 investigating their respective excellencies. 



Our immediate concern, then, is with vegetable liee : its general 

 laws, structure, and phoenomena. And upon this subject I shall touch as 

 briefly as possible, intending it as a mere vestibule, or introduction to the 

 more important study of animal philosophy. 



Plants, then, like animals, as I have already observed, are produced by 

 generation, and through the medium of ova, or eggs. The exceptions to 

 this common rule are few, and they occur equally in both kingdoms. The 



