THE CONDITION OF OLD AGE 33 



delicate. Those of you who have seen fresh liver in 

 the butcher's shop know what a flabby organ it is, and 

 yet though it is surrounded by the elements of con- 

 nective tissue, which with great zest and eagerness 

 produce tough fibres, it never gives way to them. 

 The connective tissue is held back by the soft liver 

 and kept in place by it. The liver is, so to speak, a 

 nobler organ than the connective tissue and holds 

 sway ordinarily ; but in old age, when the nobler 

 organs lose something of their power, then the con- 

 nective tissue gets its chance, grows forward, and fills 

 up the desired place, and acquires more and more 

 a dominating position. We can see this process in 

 the brain of man or the brain of the bee. That 

 which is the nervous material proper, microscopic 

 examination shows us to be diminished everywhere 

 in the old bee and in the old man, and the tissue 

 which supports it, which is of a coarser nature and 

 cannot perform any of the nobler functions, fills 

 up all the space thus left, so that the actual composi- 

 tion of the brain is by this means changed. There 

 is, you see, therefore, during the atrophy of the brain, 

 not only a diminution of the organ as a whole, but 

 there is the further degradation which consists in the 

 yielding of the nobler to the baser part, if I may so 

 express myself. That, you recognise, necessarily im- 

 plies a loss of function. The brain cannot under 

 senile conditions do the sort of fine and efficient work 

 which it could do before. Now if we go on from in- 

 sects to yet lower organisms, we see less and less 



