Lamarckism, for example, made the formation of organs a response to external conditions imposed by the environment. The elephant, according to this view, being maladjusted to its environment by reason of its clumsy bulk, developed a trunk by using its nose to compensate for its lack of pliancy and agility. Here the use or function precedes the organ and molds the latter to its need. Darwinism agrees with Lamarckism in making the environment the chief arbiter of modification. Its explanation of the elephant’s trunk, however, is negative rather than positive. This animal, it tells us, developed a trunk, because failure to vary in that useful direction would have been penalized by extermination. Wilson presents, in a very graphic manner, the appalling problem which confronts evolutionists who seek to explain the adaptations of organisms by means of environmental factors. Referring, apparently, to Henderson’s “Fitness of the Environment,” he says: “It has been urged in a recent valuable work ... that fitness is a reciprocal relation, involving the environment no less than the organism. This is both a true and suggestive thought; but does it not leave the naturalist floundering amid the same old quicksands? The historical problem with which he has to deal must be grappled at closer quarters. He is everywhere confronted with specific devices in the organism that must have arisen long after the conditions of environment to which they are adjusted. Animals that live in water are provided with gills. Were this all, we could probably muddle along with the notion that gills are no more than lucky accidents. But we encounter a sticking point in the fact that gills are so often accompanied by a variety of ingenious devices, such as reservoirs, tubes, valves, pumps, strainers, scrubbing brushes, and the like, that are obviously tributary to the main function of breathing. Given water, asks the naturalist, how has all this come into existence and been perfected? The question is an inevitable product of our common sense.” (Smithson. Inst. Rpt. for 1915, p. 405.) Impressed with the difficulty of accounting for the phenomena of organic adaptation by means of the far too general and unspecific influence of the environment, the orthogenetic school of transformism inaugurated by Nägeli, Eimer, and Kölliker repudiated this explanation, and sought to explain organic evolution on the sole basis of internal factors, such as “directive principles,” or germinal determinants. According to this conception, the elephant first developed his trunk under the drive of some internal agency, and afterwards sought out an environment in which the newly-developed trunk would be useful. In other words, orthogenesis makes the organ precede the function, and is therefore the exact reverse of Lamarckism.