i 3 o AGE, GROWTH, AND DEATH 



ovum at 0.004 cubic millimetre and of the child at 

 birth at 3 to 4,000,000 cubic millimetres, a billion 

 times increase. Assuming the weight of a man 

 of twenty years at 130 pounds, the increase after 

 birth would be as 1:16. He thereupon emphasises 

 the enormous diminution of cell production which 

 must be assumed. It is a pleasure to have my own 

 views confirmed by so distinguished a colleague. 



I attempted to convince you in the first and second 

 lectures that that which we called the condition of 

 old age, is merely the culmination of changes which 

 have been going on from the first stage of the germ 

 up to the adult, the old man or woman. All through 

 life these changes continue. The result is senility. 

 But if, as the phenomena of growth indicate to us so 

 clearly, it be true that the decline is most rapid at 

 first, then we must expect from the study of the very 

 young stages to find a more favourable occasion for 

 analysis of the factors which bring about the loss in 

 the power of growth and of change as the final result 

 of which we encounter the senile organism. Not 

 from the study of the old, therefore, but from the 

 study of the very young, of the young embryo, and of 

 the germ, are we to expect insight into the compli- 

 cated questions which we have begun to consider to- 

 gether. I shall hope in the next lecture to prove 

 to you that the supposition which has guided my own 

 observations is correct, and to be able to show you 

 that we do actually, from the study of the developing 

 embryo, glean some revelations of the cause of old age. 



