II 



CYTOMORPHOSIS : THE CELLULAR CHANGES OF AGE 



TADIESAND GENTLEMEN: I endeavoured 

 in my last lecture to picture to you, so far as 

 words could suffice to make a picture, something of 

 the anatomical condition of old age in man, and to 

 indicate to you further that the study merely of that 

 anatomical condition is not enough to enable us to 

 understand the problem we are tackling, but that we 

 must in addition extend the scope of our inquiry so 

 that it will include animals and plants, for since in all 

 of these living beings the change from youth to old 

 age goes on, it follows that we can hardly expect an 

 adequate scientific solution of the problem of old age 

 unless we base it on broad foundations. By such 

 breadth we shall make our conclusion secure, and we 

 shall know that our explanation is not of the charac- 

 ter of those explanations which I indicated to you in 

 the last lecture, which are so-called " medical," and are 

 applicable only to man, but rather will our explanation 

 have in our minds the character of a safe, sound, and 

 trustworthy biological conclusion. The problem of 

 age is indeed a biological problem in its broadest 

 sense, and we cannot study, as we now know, the 



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