In regard to the criterion of vitalistic phenomena Driesch makes the following statement: “On the current view we are inclined to see, in the formative changes, actual causes at work that even initiate those processes that we call stimuli; we do so because we pretend at present to know something of the special mechanism by which the formative changes work. The effects come into play through a causal union of simple processes of a physical-chemical sort that we may call a chain of stimuli. From the new point of view, the initiatory stimulus is not an initiatory cause or the effect of a causally united chemico-physical phenomenon. The stimulus is, from this point of view, a true stimulus, but the effect is not a true effect of its initiation, but is rather to be designated a responsive effect, for there is no connecting chain of stimuli. It is in the place of the latter that the vitalistic view appears. The only data of a machine sort in the conception are the arrangements for the reception and guidance of the stimulus, perhaps also the means for carrying out the response effect; for the machine data are only the prerequisites of the phenomena, but in themselves do not bring about the result.” Driesch finds in this argument a _demonstration_ of the vitalistic doctrine, but vitalism, of course, of a very special kind. Without a more elaborate presentation of his view it is not possible to give a detailed criticism of his conclusions; but a few of the more obvious objections that may be brought against this view may be discussed. The assumption of “action at a distance” does not, I think, in any way help to make the phenomenon clearer. The formation of a typical larva of normal proportions from a piece of an egg is just as mysterious after the assumption of an “action at a distance” of a proportionate sort as it was before. Driesch has introduced into the argument to establish a vitalistic standpoint one of the most obscure ideas of physical science. There is, so far as I can see, no necessity for such an assumption, since there is present in every case a continuous medium of protoplasm, which would seem to make this idea at least superfluous. Moreover, the additional element that Driesch has added to his conception of the process, namely, an action in proportion to the size of the piece, is objectionable if for no other reason than that it attributes to the unknown principle of “action at a distance” a quality that is the very thing that ought itself to be explained. This assumption, it seems to me, begs the entire question, and we can give no better explanation why it should belong to the principle of “action at a distance” than to anything else. Far from having given a demonstration of vitalism, Driesch has, I think, in his analysis simply set up an entirely imaginary principle, which, taken in connection with other undemonstrable qualities, is called vitalism.