S44 Mr Macvicar on the Seed of the Stipa Pcnnata. 



juries, and a tenacity is imparted to it, which would even be 

 ridiculous in the higher animals. Thus, it is very absurd to 

 think of a man continuing to live after his head had been cut 

 off; yet low in the scale, we find many species which, when deca- 

 pitated, can serve themselves with new heads, as efficient as those 

 of which they had been deprived, and scarcely differing from 

 them, but in their paler complexion. Of this circumstance Mr 

 Dalyel availed himself, in his very interesting investigation of 

 the Planariae. For when he wished to know how many eyes 

 the Planaria nigra possessed, not being able to distinguish them 

 on account of the black colour of the animal, he decapitated seve- 

 ral, and was then able to count the eyes in the pale reproduced 

 heads. As to legs, the amputation of one of which without sur- 

 gical aid, would prove inevitably fatal to a man, there are many 

 animals which seem to part with them without much inconveni- 

 ence ; while there are others (as the crabs), which, according to 

 recent observations, seem to scorn the possession of a leg when in- 

 jured, casting it triumphantly from them. 



If we descend still farther among animals still more beset by 

 enemies and accidents, we find species which really seem to be 

 *' immortal under the edge of the knife,"" which to cut in pieces, 

 is only to give being to so many individuals as perfect as that 

 which was attacked. 



The action of the same admirable law is illustrated in the re- 

 production of the race. Thus in the most perfect animals, the 

 species is divided into two groups, only one of which is capable 

 of producing offspring. As we descend, this bisexual character 

 is obliterated, and every individual, often without the presence 

 of another, acquires this power. Still lowerj not only do we 

 find each animal provided with a specific apparatus for this pur- 

 pose, but the same end accomplished in other ways also, as by 

 gems and spontaneous division. 



In the vegetable economy, which runs parallel to that of ani- 

 mals, we observe the same law to operate. Thus the oak, which 

 cannot easily be destroyed, the individual life of which survives 

 the sweep of many ages, can only be reared from an acorn ; 

 while the tender moss, which springs up among the turf beneath 

 which its roots are spread, or the parasitic lichen on its trunk 

 and branches, the lives of which are subject to a multitude of 



