ORGANS OF REPRODUCTION. 



absorbed fluids, losing sucli of tlicir aqueous and 

 aerifonn principles as are useless for nutrition, 

 and thus acquiring new properties ; after which, 

 pursuing a retrograde course they become the 

 tme aliment of the plant. 



We thus see, that, although nutrition in plants 

 has a great similarity to the same function in 

 animals, it yet differs essentially from the latter. 

 Thus animals introduce by their mouth the 

 different substances by which they are nourished; 

 while plants absorb, in the interior of the earth, 

 by the imbibing orifices which terminate their 

 roots, water impregnated with substances which 

 are either necessary or useful for their nutrition. 



In animals, the substances that have been in- 

 troduced pass along a single canal, from the 

 mouth to the place where the substance which 

 is alone directly subservient tp nutrition (the 

 cli^le,') is to be separated from the useless parts. 

 In vegetables the same phenomena take place ; 

 the absorbed fluids pass through a certain course 

 before they arrive at the leaves, in which the 

 parts essential to nutrition are separated from 

 those which are useless. Both animals and vege- 

 tables eject the substances which are unfit for 

 their nutrition. 



One of the most striking differences between 

 vegetables and animals consists in the circum- 

 stance, that the former are essentially nourished 

 by inorganic substances, such as water, carbon, 

 hydrogen, &c., whereas the substances wliich 

 are subservient to the nutrition of animals are 

 organic, and derived from the animal and vege- 

 table kingdoms. 



The chyle, by which the nutrition of animals 

 is effected, mingles with the blood, which it 

 continually renews and keeps up in due quantity, 

 circulates through all parts of -the body, and 

 serves for the development and nutrition of the 

 organs. The sap of plants, after being exposed 

 in the leaves to the influence of the air, which 

 changes its nature and properties, descends into 

 all parts of the vegetable, caiTying into them 

 the materials necessary for their growth, and 

 thus effecting the development of all their 

 parts. 



CHAP. XII. 



THE ORGANS OV REPRODUCTION, AND HISTORY OF 

 THEIR DISCOVERY. 



The Organs of reproduction, which are also 

 called Organs . of Fructification, are those by 

 which the preservation of species and the pro- 

 pagation of races are effected. Their office is 

 not less important than that of the organs whose 

 structure and uses we have already examined ; 

 for, if the latter are necessary for the existence 



of the individual, and the development of all 

 its parts, the organs of reproduction are equally 

 necessary to enable the individual to procreate 

 others similar to itself, by which its species may 

 be renewed and perpetuated. 



In plants, the flower, the fruit, and the various 

 parts of which they are composed, constitute 

 the organs of reproduction. 



Here we find a great lesemblance between 

 animals and vegetables. Both are provided with 

 particular organs, which by their mutual influ- 

 ence concur in producing the most important 

 function of their life. Generation is the ultimate 

 object for which nature has created the various 

 organs of vegetables and animals. They exhibit 

 the most perfect similarity in respect to this 

 great function. From the action which the 

 male organ exercises upon the female organ, 

 fecundation takes place, by which ■ the embryo, 

 yet in the rudimentary state, receives and pre- 

 serves the vivifying principle of life. Here, 

 however, we remark the modifications which 

 nature has impressed upon these two great 

 classes of organized beings. Most animals are 

 furnished at birth with the organs which are, at 

 a future period, to effect their reproduction. 

 These organs remain in a state of torpidity until 

 the period when nature, imparting to them a 

 new energy, renders them capable of performing 

 the offices for which they were destined. Vege- 

 tables, on the contrary, are, at their first appear- 

 ance, destitute of sexual organs, these not being 

 developed by nature until the moment when 

 they are to be employed for the purpose of fe- 

 cundation. Another great dissimilarity between 

 animals and vegetables is, that, in the former, 

 the sexual organs are capable of performing the 

 same function several times, and exist during 

 the whole life of the individual which bears 

 them ; while in vegetables, which have a soft 

 and delicate texture, these organs have only a 

 temporary existence, make their appearance for 

 the purpose of accomplishing the views of nature, 

 and fade and disappear whenever they have per- 

 formed their office. 



We admire the wisdom by which Nature has 

 regulated the distribution of sexes in organized 

 beings. Vegetables,- which are invariably fixed 

 to the place in which they have sprung to life 

 and are destitute of the locomotive faculty, 

 usually bear on the same individual the two 

 organs by the mutual action of which fecun- 

 dation is to be effected. Animals, on the other 

 hand, which, being possessed of will and the 

 faculty of moving, can pass in any direction 

 from one place to another, generally have the 

 sexes separated upon distinct individuals. For 

 this reason, the union of the sexes in one indi- 

 vidual is as common in vegetables as it is rare 

 among animals. 



The flower is essentially constituted by the 



