494 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1912, 



substance — which in certain forms may be regarded as the simplest 

 type of living matter, while it is certainly the fons et origo of all active 

 chemical processes within most cells — have shown how much less 

 complex in chemical nature this substance may be than physiologists 

 were a few years ago accustomed to regard it. On this and other 

 grounds it has lately been independently suggested by Prof. Minchin 

 that the first living material originally took the form, not of what is 

 commonly termed protoplasm, but of nuclear matter or chromatin: 

 a suggestion which appears by no means improbable. 



If the honored names of Charles Darwin, Ernst Hackel, and August 

 Weismann are not found in the following pages, it is because exigen- 

 cies of space and time rendered it necessary to deal mainly with the 

 more modern developments of this chapter of evolutionary histoiy. 

 For other but not less cogent reasons all metaphysical speculations 

 on the subjects dealt with have been avoided. The study of natural 

 knowledge, as the Royal Society still quaintly describes in its title the 

 investigation of the phenomena of nature, is never properly advanced 

 if mixed up with the "supernatural" or if metaphysics is appealed to 

 for the explanation of scientific problems which can not at once be 

 solved by ordinary scientific methods; and it behooves us to eliminate 

 all considerations involving the intervention of superantural agencies 

 just as much in connection with scientific inquiries into the nature 

 and origin of life as with all other matters which are properly the 

 subject of scientific investigation. This is not materialism, but 

 common sense. 



The first part of the subject of this address is dealt with at consider- 

 able length and in a strictly scientific spirit by Le Dantec in "The 

 Nature and Origin of Life," as well as by Dastre in the book mentioned 

 on the next page. To works such as these the reader is referred for 

 the numerous details which it is impossible to include within the limits 

 of a short essay. 



DEFINITION. 



Eveiybody knows, or thinks he knows, what life is; at least we 

 are all acquainted with its ordinaiy, obvious manifestations. It 

 would therefore seem that it should not be difficult to find an exact 

 definition. The quest has, nevertheless, baffled the most acute 

 thinkers. Herbert Spencer devoted two chapters of his "Principles 

 of Biology" to the discussion of the attempts at definition which 

 had up to that date been proposed, and himself suggested another. 

 But at the end of it all he is constrained to admit that no expression 

 had been found which would embrace all the known manifestations 

 of animate, and at the same time exclude those of admittedly 

 inanimate, objects. 



The ordinary dictionary definition of life is "the state of living." 

 Dastre, following Claude Bernard, defines it as "the sum total of 



