354 PRINCIPLES OF CLASSIFICATION. 



688. But, whatever it may be wliicli we practically or philosophi- 

 cally regard as the vegetable individual, it is evident that plants as 

 well as animals occur in a continued succession of organisms or 

 beings Avliich stand in the relation of parent and offspring. Each 

 particular sort is a chain, of which the individuals are the links. 

 To this chain, or (as expressed by Linnaeus) this perennial succes- 

 sion of individuals, the natural-historian applies the name of 



689. Species (14). Every one knows that the several sorts of 

 plants and animals steadily reproduce themselves, or, in other words, 

 keep up a succession of essentially similar individuals, and under 

 favorable circumstances increase their numbers. Each particular 

 kind of cultivated plant or domesticated animal is represented before 

 our eyes in a mass of individuals, which we know from observation 

 to a certain extent, and from necessary inference, have sprung 

 from the same stock. And common observation has led people 

 everywhere to expect that the different sorts will continue true to 

 their kind, or at least to conclude tliat the different sorts of plants 

 or of animals do not shade off one into another by insensible grada- 

 tions, like the colors of the rainbow, as would have been the case if 

 there were not distinct kinds at the beginning, and if their distinc- 

 tions were not kept up, unmingled, and transmitted essentially un- 

 altered, from generation to generation. So we naturally assume that 

 the Creator established a definite, although a vast, number of types 

 or sorts of plants and animals, and endowed them with the faculty 

 of propagation each after its kind ; and that these have so continued 

 unchanged in all their essential characteristics. Out of these gen- 

 eral observations and conceptions the idea of species must have origi- 

 nated ; from them we deduce its scientific definition. Name!}', tliat 

 the species is, abstractly, the type or original of each sort of plant, 

 or animal, thus represented in time by a perennial succession of like 

 individuals, or, concretely, that it is the sum of such series or con- 

 geries of individuals ; and that all the descendants of the same stock, 

 and of no other, compose one species. And, conversely, as we can 

 never trace back the genealogy far, Ave naturally infer community 

 of origin from fraternal resemblance ; that is, we refer to the same 

 species those individuals which are as much alike as those are 

 which Ave know to have sprung from, the same stock.* 



* We use the •word stock advisedly, (and in one of its proper meanings, that 

 of the original or originals of a lineage, ) to avoid the assertion or denial of the 



