86 ON ORGANIZED BODIES, 



life, by the ancients, as in the present day.* The seed is sometimes naked, 

 but more generally covered with a pericarp, whence plants become naturally 

 divided into the two grand arrangements of gymnospermous and angiosper- 

 mous. The pericarp is of various forms and structures ; and of these the 

 more common are the legume, silique, or silicle, being merely varieties of 

 what, among ourselves, is denominated in popular language cod or pod ; the 

 loment which is a kind of pod not so frequent as either of the former, but of 

 "which we have an instance in the mimosas and the cassia fistula; the pome 

 or core-apple, of which we have instances in the common apple and the pear; 

 the drupe, or stone-apple, instances of which occur to us in the plum, cherry, 

 and almond ; the glume or chaff; the berry ; the acinus or conglomerate berry, 

 as in the rasp; the nut; and the capsule. f 



Stripping off this outer covering, we find the seed to consist internally of a 

 corculum, or heartlet, and externally of a fleshy or parenchymatous sub- 

 stance, surrounded with a double integument, sometimes single, sometimes 

 .bifid, and sometimes more than bifid ; and hence denominated monocotyle- 

 donous, dicotyledonous, polycotyledonous. In popular language these are 

 called seed-lobes, or seed-leaves : and in the phaseolous -vulgaris, or common 

 kidney-bean, we have as striking an instance as in any plant, and which every 

 one must have noticed, just peeping in two distinct segments above the ground, 

 as soon as the seed has begun to germinate. It was very generally supposed 

 formerly, and is still supposed by some botanists, that the seeds of various 

 orders of plants, as the mosses, fungi, and algas, are acotyledonous, or totally 

 destitute of a cotyledon of any kind. But as many, perhaps most, plants of 

 this kind have of late been found to possess some such parenchyma, we have 

 great reason for believing that this organ is universal, and that there is no 

 such thing as an acotyledonous seed in the whole vegetable kingdom. In 

 reality, the cotyledon appears absolutely necessary for the germination and 

 future growth of the seed, and may hence be denominated its lungs or pla- 

 centule. Like the perfect plant, it possesses lymphatics and air-vessels. 

 Through the former of these it absorbs the moisture of the soil into which it is 

 plunged, decomposes a part of it into its elementary principles, and conducts 

 those principles, together with the undecomposed water, to the corcle or 

 heartlet, which becomes stimulated to the process of germination by the oxy- 

 gen thus set at liberty. 



Mrs. Ibbetson has attempted to prove that the cotyledon is of no use 

 whatever for the purpose of nourishment ; which, according to her observa- 

 tions, is only conveyed to the corcle by what she calls a system of nourishing 

 vessels, altogether distinct from the cotyledon. It is not very clear, however, 

 what is here meant by nourishing vessels ; nor can we for a moment admit 

 that so large an organ as the cotyledon, and apparently so important, can be 

 designed for no other office than merely, as this lady conjectures, to screen 

 the primordial leaves from the light and air on their first formation."! 



According to Mr. Mirbel's experiments, as detailed in the Memoirs of the 

 National Institute, the soil and the albumen in the cotyledon are both con- 

 cerned in the developement of the germ ; and both continue to contribute 

 conjointly till the albumen is entirely absorbed : at which time the plant has 

 strength enough to derive from the soil or the atmosphere the nourishment it 

 requires from this period. In this respect the albumen of the cotyledon cor- 

 responds with the vitellus of the hen's egg. 



In marine plants that are destitute of a radicle, as the water caltrop (trapa 



* Ourw 6' woToxel /uxpa Stvdpea Trpair 



So plants, like animals, uprise to air, 

 Anil in green eggs young olives olives bear 



And upon this beautiful verse, which he has preserved as a fragment, Aristotle remarks, r6 TS ydp wbv 

 Kvtjpd tffri, teat K TWOS avrov -yiyvsTai rb ^wov. " For the egg is the conception, and after the same manner 

 the animal is created." De Gcnerat. Animal, i. 23. 



t Compare Knight's General Theory of Vegetable Physiology, Horticultural Transactions, vol. i. p. 217 

 with Nicholson's Journal, vol. xxxii. p. 350- 

 J Nicholson's Journal, vol. xxvii. 9. 



