their history yields powerful indirect evidence in support of the position that origin of life apart from germ is unknown. It is, however, desirable here, in order to give completeness to our view of the present situation, to remark that among scientific men there are some who have no expectation of a scientific explanation of the origin of life; while others are exceedingly hopeful that such explanation may be reached, in the latter class appearing naturally all those who openly proclaim against what they name an "incomprehensible act of creation," and voluntarily place themselves in antagonism to religious thought. It is, therefore, of some consequence to indicate the grounds on which such opposite views rest. On the one side, Professor Tait, while suggesting the possibility of yet discovering the physical principles which determine life, nevertheless adds, "Let no one imagine that, should we ever penetrate this mystery, we shall thereby be enabled to produce, except from life, even the lowest form of life."[AQ] On the other hand Professor Schmidt of Strasburg maintains the opposite view, affirming that "the investigation of nature does not shrink from enrolling _life_, and the processes of life in the world of the comprehensible."[AR] This latter assertion is not to be accounted for on the ground that Schmidt is the ardent admirer and defender of the theory of origin of species by natural selection, for it is clear, as he maintains in replying to Max Müller, that "the origin of life has in fact nothing to do with actual Darwinism, or natural selection, unless the principle of selection be extended to the inorganic world of matter."[AS] Mr. Darwin himself does not suggest any such extension, and his theory of species is not chargeable with it. It should, indeed, be clearly recognized on all hands that the naturalist confines himself to a narrower range of inquiry, taking existing phases of life as the subject of his study. Accordingly, whoever claims that the origin of life comes within the compass of science, does so on the ground that there is no demarcation between the organic and the inorganic,--that the former may arise directly from the latter,--and so he commits himself to a doctrine of descent world-wide in its application, involving development in the world of all its varied phases of existence from a mass of unorganized matter.