41 



ON THE NATURE OF LIVING ORGANISMS. 



By A. E. Hilton. 



{Read January ISth, 1907.) 



The question as to what a living organism really is, in its 

 essential nature, is a singularly difficult one to answer. It is 

 probable, indeed, that a complete answer will not be possible for 

 a long time to come. Yet it is well, now and then, to formulate 

 as far as we can a provisional answer, and to inquire what 

 biology up to date can teach us towards making our notions 

 a little clearer. Unless we do so, much of the suggestiveness 

 of our exhibits and lectures will be largely lost ; and the 

 purpose of this paper is to help those whose opportunities for 

 study are but limited. 



Science tells us to-day that living organisms are " automatic 

 chemical machines." To those who regard life as a mysterious 

 principle, distinct from, and not inherent in, the material which 

 it animates, this description seems very inadequate. We must 

 remember, however, that science knows nothing of life apart 

 from matter ; and that scientific definitions, cut and dried though 

 they be, do but express known facts resting upon unknown 

 causes. Mystery still remains, but nowadays it lies deeper, 

 because the electron theory has made knowledge more pene- 

 trative. 



That all living things, irrespective of size, colour, form, or 

 habit, have a similar material foundation, has been well known 

 for the last forty years. In a famous lecture delivered in 1868, 

 Huxley described this substance, common to all organisms, as 

 the " physical basis of life." At that time it was called " proto- 

 plasm," but now it is more correctly and simply known as 

 " plasm " ; and it is this indispensable plasm, the vehicle of all 

 vital activities, which science tells us is "automatic chemical 

 machinery." What we have to do is to grasp the significance of 

 that definition, to convert it into a useful working idea. 



