of developmental venture do from time to time occur in the race histories even of the dullest and most dead-level organisms under the name of “sports;” but they would hold that even these occur most often and most happily to those that have persevered in well-doing for some generations.  Unto the organism that hath is given, and from the organism that hath not is taken away; so that even “sports” prove to be only a little off thrift, which still remains the sheet anchor of the early evolutionists.  They believe, in fact, that more organic wealth has been made by saving than in any other way.  The race is not in the long run to the phenomenally swift nor the battle to the phenomenally strong, but to the good average all-round organism that is alike shy of Radical crotchets and old world obstructiveness.  Festina, but festina lente—­perhaps as involving so completely the contradiction in terms which must underlie all modification—­is the motto they would assign to organism, and Chi va piano va lontano, they hold to be a maxim as old, if not as the hills (and they have a hankering even after these), at any rate as the amoeba.

To repeat in other words.  All enduring forms establish a modus vivendi with their surroundings.  They can do this because both they and the surroundings are plastic within certain undefined but somewhat narrow limits.  They are plastic because they can to some extent change their habits, and changed habit, if persisted in, involves corresponding change, however slight, in the organs employed; but their plasticity depends in great measure upon their failure to perceive that they are moulding themselves.  If a change is so great that they are seriously incommoded by its novelty, they are not likely to acquiesce in it kindly enough to grow to it, but they will make no difficulty about the miracle involved in accommodating themselves to a difference of only two or three per cent. {72a}

As long as no change exceeds this percentage, and as long, also, as fresh change does not supervene till the preceding one is well established, there seems no limit to the amount of modification which may be accumulated in the course of generations—­provided, of course, always, that the modification continues to be in conformity with the instinctive habits and physical development of the organism in their collective capacity.  Where the change is too great, or where an organ has been modified cumulatively in some one direction, until it has reached a development too seriously out of harmony with the habits of the organism taken collectively, then the organism holds itself excused from further effort, throws up the whole concern, and takes refuge in the liquidation and reconstruction of death.  It is only on the relinquishing of further effort that this death ensues; as long as effort endures, organisms go on from change to change, altering and being altered—­that is to say, either killing themselves piecemeal in deference to the surroundings or killing the surroundings piecemeal to suit themselves.  There is a ceaseless higgling and haggling, or rather a life-and-death struggle between these two things as long as life lasts, and one or other or both have in no small part to re-enter into the womb from whence they came and be born again in some form which shall give greater satisfaction.