After arriving at this conclusion the following admission is a decided anticlimax: “The question, however, arises as to whether the capacity of each part for regeneration results from special process of adaptation, or whether regeneration occurs as the mere outcomewhich is to some extent unforeseen--of the physical nature of an animal. Some statements which have been made on this subject seem hardly to admit of any but the latter explanation.” After showing that some newts confined in aquaria attacked each other, “and several times one of them seized another by the lower jaw, and tugged and bit at it so violently _that it would have been torn off had I not separated the animals_,”[40] and after referring to the regeneration of the stork’s beak, Weismann concludes: “Such cases, the accuracy of which can scarcely be doubted, indicate that the capacity for regeneration does not depend only on the special adaptation of a particular organ, but that a general power also exists which belongs to the whole organism, and to a certain extent affects many and perhaps even all parts. By virtue of this power, moreover, simple organs can be replaced when they are not specially adapted for regeneration.” The perplexity of the reader, as a result of this temporary vacillation on Weismann’s part, is hardly set straight by the general conclusion that follows on the same page: “We are, therefore, led to infer that the general capacity of all parts for regeneration may have been acquired by selection in the lower and simpler forms, and that it gradually decreased in the course of phylogeny in correspondence with the increase in complexity of organization; but that it may, on the other hand, be increased by special selective processes in each stage of its degeneration, in the case of certain parts which are physiologically important and are at the same time frequently exposed to loss.” There are certain statements of facts in the same chapter that are incorrect, and the argument is so loose and vague that it is difficult to tell just what is really meant. As a misstatement of fact I may select the following case: It is stated that lumbriculus does not have the power of regenerating laterally if cut in two, and it is argued that a small animal of this form could rarely be injured at the side without cutting the animal completely in two. As a matter of fact, lumbriculus can regenerate laterally, and very perfectly, as any one can verify if he takes the trouble to perform the experiment; but, of course, if the whole animal is split in two lengthwise the pieces die, or if a very long piece is split from one side the remaining piece usually disintegrates. If, however, the anterior end is split in two for a short distance, or if a piece is partially split in two, the half remaining in contact with the rest of the piece completes itself laterally. The same result follows also in the earthworm.