248 AGE, GROWTH, AND DEATH 



practical question, but rather of scientific interest, for 

 we must admit that the production of young individ- 

 uals is, on the whole, very well accomplished and much 

 to our satisfaction. But in regard to growing old, in 

 regard to senescence, the matter is very different. 

 There we should, indeed, like to have some principle 

 given to us which would retard the rate of senescence 

 and leave us for a longer period the enjoyment of our 

 mature faculties. I can, as you have readily surmised 

 by what I have said to you, present to you no new rule 

 by which this can be accomplished, but I can venture 

 to suggest to you that in the future deeper insight 

 into these mysteries probably awaits us, and that there 

 may indeed come a time when we can somewhat reg- 

 ulate these matters. If it be true that the growing old 

 depends upon the increase of the protoplasm, and the 

 proportional diminution of the nucleus, we can perhaps 

 in the future find some means by which the activity of 

 the nuclei can be increased and the younger system 

 of organisation thereby prolonged. That is only a 

 dream of the possible future. It would not be safe 

 even to call it a prophecy. But stranger things and 

 more unexpected have happened, and perhaps this will 

 also. 



I do not wish to close without a few words of warn- 

 ing explanation. The views which I have presented 

 before you in this series of lectures I am personally 

 chiefly responsible for. Science consists in the dis- 

 coveries made by individuals, afterwards confirmed and 

 correlated by others, so that they lose their personal 



