444 Transactions of the Society. 



metabolic rate ; but there are counteractive processes of reduction, 

 removal, and de-differentiation, when the metabolic stream erodes 

 its bed instead of depositing materials. These are marked by 

 acceleration in metabolic rate, and constitute rejuvenescence. 

 " It is certain," Child says, " that the new individuals which arise 

 by division or budding from other individuals, or from experi- 

 mentally isolated pieces, are to some extent physiologically younger 

 than the parent individual from which they arose." 



The idea of a see-saw between processes of senescence and 

 rejuvenescence finds many illustrations among the lower animals ; 

 but what of higher levels ? Child finds some interesting evidence 

 that the early developmental stages of a number of animal types, 

 before specialization of cells sets in, are conspicuously young in 

 the physiological sense. The germ -cells themselves are very 

 stable condensations of hereditary items, but in the early develop- 

 ment there is a time of reconstitution, of de- differentiation, of 

 relaxation. If there is any soundness in this view, in support of 

 which data are of course submitted, we may perhaps recognize 

 another opportunity for variation, namely, in the very young 

 embryo, where the alleged rejuvenescence may include possibilities 

 of rearrangement and, as it were, re-tuning. 



§ 7. At this stage we must refer to Professor Bateson's 

 interesting suggestion in regard to the possibilities of gain by 

 loss, of the emergence of mutations by the removal of inhibiting 

 factors. There are a few people who believe that reptiles came 

 from birds, not birds from reptiles, and fishes from amphibians, 

 not amphibians from fishes, but this topsy-turvy view of evolution 

 is not confirmed by the rock-record. It is quite possible, however, 

 that the first organisms were not the " simple drops of living 

 matter " that people talk about too easily ; it is possible that they 

 were only apparently simple (like some great geniuses), but in 

 reality rich in complexities which it has taken many millions 

 of years to unravel. In his Presidential Address to the British 

 Association, meeting in Australia in 1914, Professor Bateson said 

 that " we must begin seriously to consider whether the course of 

 Evolution can at all reasonably be represented as an unpacking 

 of an original complex which contained within itself the whole 

 range of diversity which living things present. ... As we have 

 got to recognize that there has been an Evolution, that somehow 

 or other the forms of life have arisen from fewer forms, we inay as 

 well see whether we are limited to the old view that evolutionary 

 process is from the simple to the complex, and whether after all 

 it is conceivable that the process was the other way about. . . . 

 At first it may seem rank absurdity to suppose that the primordial 

 form or forms of protoplasm could have contained complexity 

 enough to produce the divers types of life. But is it easier to 

 imagine that these powers could have been conveyed by extrinsic 



