INTRODUCTORY ESSAY. XXV 



38. Before dismissing this subject, I may revert once more to the opposite doctrine, which 

 regards species as immutable creations, and this principally to observe that the arguments in its 

 favour have neither gained nor lost by increased facibties for investigation, or by additional means 

 for observation. The facts are unassailable that we have no direct knowledge of the origin of any 

 wild species; that many are separated by numerous structural peculiarities from all other plants; 

 that some of them invariably propagate their like; and that a few have retained their characters 

 unchanged under very different conditions and through geological epochs. Recent discoveries have 

 not weakened the force of these facts, nor have successive thinkers derived new arguments from 

 them ; and if we hence conclude from them that species are really independent creations and immu- 

 table, though so often illimitable, then is all further inquiry a waste of time, and the question of 

 their origin, and that of their classification in Genera and Orders, can, in the present state of sci- 

 ence, never be answered, and the only known avenues to all means of investigation must be con- 

 sidered as closed till the origin of life itself is brought to light. 



39. Of these facts the most important, and indeed the only one that affords a tangible argument, 

 is that of genetic resemblance. To the tyro in Natural History all similar plants may have had one 

 parent, but all dissimilar plants must have had dissimilar parents. Daily experience demonstrates 

 the first position, but it takes years of observation to prove that the second is not always true. 

 There are, further, certain circumstances connected with the pursuit of the sciences of observation 

 which tend to narrow the observer's views of the attributes of species; he begins by examining a 

 few individuals of many extremely different lands or species, which are to him fixed ideas, and the 

 relationships of which he only discovers by patient investigation; he then distributes them into 

 Genera, Orders, and Classes, the process usually being that of reducing a great number of dissimilar 

 ideas under a few successively higher general conceptions ; whilst with the history of the ideas them- 

 selves, that is, of species, he seldom concerns himself. In a study so vast as botany, it takes a long 

 time for a naturalist to arrive at an accurate knowledge of the relations of Genera and Orders if he 

 aim at being a good systematist, or to acquire an intimate knowledge of species if he aim at a 

 profLLaey jn local Floras, and in both these pursuits the abstract consideration of the species itself 

 is generally lost sight of; the systematist seldom returns to it, and the local botanist, who finds the 

 minutest differences to be hereditary in a limited area, applies the argument derived from genetic 

 resemblance to every hereditarily distinct form. 



40. It has been urged against the theory that existing species have arisen through the variation 

 of pre-existing ones ajid the destruction 'of intermediate varieties, that it is a hasty inference from a 

 few facts in the life of a few variable plants, and is therefore unworthy of confidence, if not of consi- 

 deration; but it appears to mejdiat the opposite theory, which demands an independent creative act 

 for each species, is an equally hasty inference from a few negative facts in the life of certain species,* 

 of which some generations have proved invariable within our extremely limited experience. These 

 theories must not, however, be judged of solely by the force of the very few absolute facts on which 

 they are based ; there are other considerations to be taken into account, and especially the conclusions 

 to which they lead, and their bearing upon collateral biological phenomena, under which points of 

 view the theory of independent creations appears to me to be greatly at a disadvantage ; for according 

 to it every fact and every phenomenon regarding the origin and continuance of species, but that of 

 their occasional variation, and their extinction by natural causes, and regarding the rationale of classi- 



* See paragraph 4, where I have stated that the grand total of unstable species probably exceeds that of the 

 stable. 



vol. i. e 



