482 BIOLOGICAL PHYSICS 



impressing themselves more or less definitely on the 

 physique^ esprit^ et morale of every descendant of Adam, 

 and can, by observation and education, qualify ourselves 

 to pronounce a more or less true and definite opinion 

 upon the life history of any one of these descendants. 



The abstract scientific importance of thus being able to 

 read life history is very great, and daily becomes greater 

 as the relationships of " man to man " widen and accumu- 

 late. It, therefore, becomes necessary that the " funda- 

 mentals " of the art should be laid on a basement of 

 exact knowledge of the " subject matter," and a scientific 

 appreciation of the factors involved, in order that it should 

 take its place as an accessory instrument for the discovery 

 of truth and a supplementary instrument for the advance- 

 ment of civilisation, without suspicion, on the one hand, 

 and with that warranty which such an instrument and 

 weapon must possess whenever used in the regulation or 

 administration of human affairs, on the other. 



In examining in some detail these " fundamentals," we 

 have become aware that the phenomena of " ageing " are 

 more or less intelligently read and understood, and "acted 

 upon," not only by uneducated man, but by the whole 

 animal, and even, to some extent, the whole vegetable 

 world, and that, therefore, they constitute, in fact, a large 

 part of the great generalisation known as the " law of 

 natural selection," as it is revealed to the organic world. 

 The occurrence of " ageing," as here indicated, may be 

 described as, in great part, innate, and the production 

 of heredity, impressed on the succeeding generations of 

 organic forms, and transmitted with them for purposes of 

 organic evolution, racial progress, and differentiation. It 

 thus becomes one of the most universally possessed attributes 

 of organic life, and consequently an instrument for the 

 moulding of organic destiny, on the lines of organic 

 evolution, of the most all-pervading character and nature. 

 In the human species, with which we are more immediately 

 concerned, " ageing " lays its hand on every structure and 

 organ of the body, and every feature and trait of the mind 

 and character, overrunning and inter-penetrating the very 

 " weft and woof of life," and maintaining a consistency of 

 plan, in spite of all the alterations of environment of the 



