the “survival of the fittest,” few who are competent to grasp will have the temerity to doubt.  And to many, that lies within it as a doctrine, and forms the fibre of its fabric, is the existence of a continuity, an unbroken stream of unity running from the base to the apex of the entire organic series.  The plant and the animal, the lowliest organized and the most complex, the minutest and the largest, are related to each other so as to constitute one majestic organic whole.  Now to this splendid continuity practical biology presents no adverse fact.  All our most recent and most accurate knowledge confirms it.  But the question is, Does this continuity terminate now in the living series, and is there then a break—­a sharp, clear discontinuity, and beyond, another realm immeasurably less endowed, known as the realm of not-life? or Does what has been taken for the clear-cut boundary of the vital area, when more deeply searched, reveal the presence of a force at present unknown, which changes not-living into the living, and thus makes all nature an unbroken sequence and a continuous whole?  That this is a great question, a question involving large issues, will be seen by all who have familiarized themselves with the thought and fact of our times.  But we must treat it purely as a question of science; it is not a question of how life first appeared upon the earth, it is only a question of whether there is any natural force now at work building not-living matter into living forms.  Nor have we to determine whether or not, in the indefinite past, the not-vital elements on the earth, at some point of their highest activity, were endowed with, or became possessed of, the properties of life.

[Illustration:  Fig. 1]

On that subject there is no doubt.  The elements that compose protoplasm—­the physical basis of all living things—­are the familiar elements of the world without life.  The mystery of life is not in the elements that compose the vital stuff.  We know them all, we know their properties.  The mystery consists solely in how these elements can be so combined as to acquire the transcendent properties of life.  Moreover, to the investigator it is not a question of by what means matter dead—­without the shimmer of a vital quality—­became either slowly or suddenly possessed of the properties of life.  Enough for us to know that whatever the power that wrought the change, that power was competent, as the issue proves.  But that which calm and patient research has to determine is whether matter demonstrably not living can be, without the aid of organisms already living, endowed with the properties of life.  Judged of hastily, and apart from the facts, it may appear to some minds that an origin of life from not-life, by sheer physical law, would be a great philosophical gain, an indefinitely strong support of the doctrine of evolution.  If this were so, and, indeed, so