The Message of Science. 41 



with its fellows. This is apparent even in the primitive 

 colony of ciliates, more evident still in volvox, and grandly 

 demonstrated in the animal organism. The cell in the 

 colony lived longer and more comfortably than when 

 struggling for life, alone ; and at the acme of organization, 

 in the vertebrate organism, we find cells which have 

 attained to what is, for a cell, immortality. In unorgan- 

 ized unicellular life, the average life-time of a cell may 

 have been less than two days, not much longer. In or- 

 ganized metazoic life, we find the neurons of the cerebral 

 cortex of an elephant, or a whale, for example, living two 

 centuries. By combining with their fellows, these cells, 

 or their descendants, have increased their span of life thirty 

 thousand times ! 



In man these brain cells often survive for a century. 

 Human beings, with life-times correspondingly prolonged, 

 would live to the age of eighteen thousand years. 



It is apparent, moreover, that these groups of brain cells 

 would live longer (for they give little evidence of having 

 exhausted their capacity for living on) but for the fact 

 that they are dragged down to death by the fate of the 

 organism, i. e., the failure of coordination among the other 

 tissue groups of cells. 



This is profoundly interesting as showing what cell life, 

 under favorable conditions, may accomplish in the way of 

 a vast longevity, from successful combinations, and 

 organization generally. There appear to be cells of the 



