one individual into the cell body of another. Whether he is right or not remains still to be determined. You will recognize, I hope, from what I have said, that we have now some kind of measure of what constitutes old and young. We can observe the difference in the proportion of protoplasm and nucleus, the increase or diminution, as the case may be, of one or the other. If it be true that there is among protozoa, among unicellular animals, anything comparable to the gradual decline in the growth power which occurs in us, we shall expect it to be revealed in the condition of the cells—to see in those cells which are old an increase in the proportion of protoplasm, and consequently a diminution in the relative amount of nucleus. That subject is now being investigated, and we shall probably know, within a few years at least, something positive in this direction. At present we are reduced to posing our question. We must wait patiently for the answer.
The scientific man has many occasions for patience. He has to make his investigations rather where he can than where he would like to. Certain things are accessible to our instruments and methods of research at the present time, but other things are entirely hidden from us and inaccessible at the present. We are indeed, more perhaps than people in any other profession of life, the slaves of opportunity. We must do what we can in the way of research, not always that which we should like most to do. Perhaps a time will come when many of the questions connected with the problems of growing old, which we can now put, will be answered, because opportunities, which we have not now, will exist then. Scientific research offers to its devotees some of the purest delights which life can bring. The investigator is a creator. Where there was nothing he brings forth something. Out of the void and the dark, he creates knowledge, and the knowledge which he gathers is not a precious thing for himself alone, but rather a treasure which by being shared grows; if it is given away it loses nothing of its value to the first discoverer, but acquires a different value and a greater usefulness that it adds to the total resources of the world. The time will come, I hope, when it will be generally understood that the investigators and thinkers of the world are those upon whom the world chiefly depends. I should like, indeed, to live to a time when it will be universally recognized that the military man and the government-maker are types, which have survived from a previous condition of civilization, not ours; and when they will no longer be looked upon as the heroes of mankind. In that future time those persons who have really created our civilization will receive the recognition which is their due. Let these thoughts dwell long in your meditation, because it is a serious problem in all our civilization to-day how to secure due recognition of the value of thought and how to encourage it. I believe every word spoken in support of that great recognition which is due
