1861.] ON TYPICAL SELECTION. 7 



existed, but that the evidence of their existence has either not yet 

 turned up, or has been altogether swept away. 



Other eminent geologists have questioned the probabiHty, if not the 

 possibiUty of this total sweeping away of the links wanted to bind 

 together, upon Mr. Darwin's supposition, the forms known to have 

 existed. I do not propose to enter into this controversy, but only to 

 remark that, whatever difficulty may arise from the absence of inter- 

 mediate forms in tracing connected lines of descent of the different 

 forms whose existence has been ascertained, it is most materially di- 

 minished on the hypothesis of typical selection, — (1) because the 

 advance in each case will be always in the same direction, and there- 

 fore the interval between one marked form and another will be indi- 

 cated by much fewer steps than are required on INIr. Darwin's 

 supposition, even if each step be very gradual ; (2) because it is con- 

 sistent with our present experience, that a very considerable amount 

 of change may take place in animal or vegetable organisms at once. 

 I will refer only to General Tom Thumb, and the Giant whose 

 skeleton is preserved in the College of Surgeons, in proof of the im- 

 portant departures from the ordinary human scale of proportion 

 which may be produced at one birth, under the ascertained laws of 

 life. Now, suppose individuals, male and female, characterized by 

 the possession of forms thus departing from the general human 

 standard, to be selected to constitute a new human species, forming the 

 centre of variations extending on all sides of the type thus manifested, 

 and the process to be repeated three or four times, hj transitions of 

 equal magnitude on each occasion, in both directions ; we should 

 arrive at forms almost as distinct from each other as Swift's men of 

 Lilhput and Brobdinguag. And yet the intermediate variations might 

 succeed each other at short intervals, and leave but scanty traces of 

 their existence in any geological record. The Lilliputian and Brob- 

 dingnagian students of geology might thus find it as difficult to 

 connect their own history with that of the present race of mankind, 

 by geological evidence, as we find it to trace the descent of Teleostean 

 fishes, or Saurian amphibians, by the same records. 



The conception of "typical selection" seems also to elucidate 

 another subject, not altogether unencumbered with difficulty on 

 Mr. Darwin's hypothesis, namely, the disappearance of types. If 

 one species is educed out of another by a modification of the sexual 

 character of some particular variety of the first, whence it acquires a 

 peculiar aptness and disposition for interbreeding, this variety would 

 be withdrawn from the circle of varieties by whose mutual action the 

 original type was preserved. Consequently the type would itself 

 have a tendency to alter ; and if several varieties were thus withdrawn 

 from any type, it would seem that this type must change into some 

 modification of itself, and take its place amid the circle of variously 

 related types evolved out of its origiiaal unity. The process would 

 be analogous to what appears to have happened in some cases, where, 

 through local circumstances or human interference, many distinct 

 varieties of the same plant or animal have been formed, as in the case 

 of wheat, of horses, of dogs, and of man himself; and the result 



