THE DESCENT OF PROTOPLASM 187 



■which would entitle it to be regarded as possessing 

 a certain amount of potential life. Of this little 

 is known, but analogical reasoning leads us to 

 suppose that it is so. The line of argument we 

 have followed, and the illustrations obtained of the 

 forms generated in the course of experiments show- 

 ing their behaviour in their development, growth, 

 multiplication and decay, suggests that living 

 matter itself was most probably a distant relative 

 of other types less obviously animate, and that it 

 was produced by some similar process through the 

 unstable aggregations of matter similar to but not 

 the same as the unstable aggregations which pro- 

 duce radio-activity, and which in turn radio-activity 

 produces in highly complex media. Forms we have 

 obtained are analogous to living types and may, as 

 we say, be called artificial forms of life, but they 

 are not the same as life as we know it to-day ; 

 they may help, however, to fill in some of the gaps 

 between living and dead matter. 



The principle of biogenesis supported and almost 

 conclusively established, though not completely so, 

 by Pasteur and Tyndall, the principle that life as 

 we know it has developed only from pre-existing 

 life, may still no doubt hold good. If these 

 artificial forms are alive it is not life as we know 

 it in nature. It is not life which can claim descent 

 from the remote past, and it is not life which will 

 hand on its own type to the distant future. 

 The idea that we should ever produce such living 

 protoplasm as we see to-day in nature, that the 



