120 NOTICES OF BOOKS. 



The second class of facts adduced is the high antiquity of many 

 timber-trees. It is unphilosophical to assume that these aged indi- 

 viduals, which are 3000 years old at a moderate computation, are the 

 parents of their kind ; whilst to suppose them even the grandsons of 

 the first parent of the species, is giving the latter a startling antiquity. 

 M. de CandoUe does not allude to the argument derived from the 

 known geological antiquity of many animal species, which, though no 

 proof of an equal duration for the life of vegetable species, renders it 

 unphilosophical to deny it ; whether we consider plants and animals 

 as parallel scries of the great kingdom of organic nature, or the fact 

 of so many animals being dependent upon individual species of plants 

 for their continued existence. 



All further inquiry into these subjects is here suddenly suspended, the 

 subject becoming complicated with, or contingent upon, the idea main- 

 tained by the inquirer as to the changes that time may or may not 

 have effected upon species. An article is devoted to this, and it opens 

 with the ominous title * Definition de TEspece/ A good resume is here 

 given of all former definitions, together with the arguments for and 

 against every clause in these. It is not our purpose to plunge into 

 this sea of difficulties ; it is enough to say that M. de Candolle believes 

 in species as having definite existences, and considers his father's defi- 

 nition, of what they may be supposed to be, almost as good as can be 



given. 



The changes which we ourselves witness are classed under — 1. Va- 

 riations. These arc slight changes in individuals or in their parts, de- 

 pending on varying seasons, climate, exposures, etc., and are of little 

 moment. 2. Monstrosities. These need no definition. 3. Varieties. 

 These involve physiological changes in the individual, which are pro- 

 pagated by division of it (budding, grafting, etc.), but which are lost 

 by seed. 4. Eaces. These are peculiar states of species, which almost 



has not^ yet been fully appreciated by geologists, which is, that specific identity of 

 fossils in the beds of far distant couiitries is opposed to these being strictly con- 

 temporaneous. (See his Essay on the Indian Fossils, in the Geological Transac- 

 tions.) ^ There is no doubt but that the pleiocene and existing Floras of Europe 

 would, if fully known, be ranked as belonging to very distinct geological epochs ; 

 but yet the pleiocene Flora of Europe may prove similar to the existing Flora of 

 America. Granting such to be the case, how, after several succeeding geological 

 epochs, when perhaps the genus Juglans will have disappeared, will it be possible to 

 classify the rocks of Europe and America without confonndiug the European pleio- 

 cene with the now existing Flora of Amurica? 



