of the world, or at all events of the thought of the world; whereas the great man of science may be moving in regions of thought that may be absolutely incommunicable to the ordinary person.  But I do not suppose that scientific greatness is a thing which can be measured by the importance of the practical results of a discovery.  I mean that a man may hit upon some process, or some treatment of disease, which may be of incalculable benefit to humanity, and yet not be really a great man of science, only a fortunate discoverer, and incidentally a great benefactor to humanity.  The unknown discoverers of things like the screw or the wheel, persons lost in the mists of antiquity, could not, I suppose, be ranked as great men of science.  The great man of science is the man who can draw some stupendous inference, which revolutionises thought and sets men hopefully at work on some problem which does not so much add to the convenience of humanity as define the laws of nature.  We are still surrounded by innumerable and awful mysteries of life and being; the evidence which will lead to their solution is probably in our hands and plain enough, if any one could but see the bearing of facts which are known to the simplest child.  There is little doubt, I suppose, that the greatest reputations of recent years have been made in science; and perhaps when our present age has globed itself into a cycle, we shall be amazed at the complaint that the present era is lacking in great men.  We are busy in looking for greatness in so many directions, and we are apt to suppose, from long use, that greatness is so inseparably connected with some form of human expression, whether it be the utterance of thought, or the marshalling of armies, that we may be overlooking a more stable form of greatness, which will be patent to those that come after.  My own belief is that the condition of science at the present day answers best to the conditions which we have learnt to recognise in the past as the fruitful soil of greatness.  I mean that when we put our finger, in the past, on some period which seems to have been producing great work in a great way, we generally find it in some knot or school of people, intensely absorbed in what they were doing, and doing it with a whole-hearted enjoyment, loving the work more than the rewards of it, and indifferent to the pursuit of fame.  Such it seems to me is the condition of science at the present time, and it is in science, I am inclined to think, that our heroes are probably to be found.

I do not, then, feel at all sure that we are lacking in great men, though it must be admitted that we are lacking in men whose supremacy is recognised.  I suppose we mean by a great man one who in some region of human performance is confessedly pre-eminent; and he must further have a theory of his own, and a power of pursuing that theory in the face of depreciation and even hostility.  I do not think that great men have often been indifferent to criticism.