34 THE DURATION OF LIFE. 



know whether spontaneous generation was the commencement of 

 life on the earth, nor have we any direct evidence for the idea 

 that the process of development of the living- world carries the 

 end within itself, or for the converse idea that the end can only 

 be brought about by means of some external force. 



I admit that spontaneous generation, in spite of all vain efforts 

 to demonstrate it, remains for me a logical necessity. We cannot 

 regard organic and inorganic matter as independent of each other 

 and both eternal, for organic matter is continually passing, without 

 residuum, into the inorganic. If the eternal and indestructible are 

 alone without beginning, then the non-eternal and destructible must 

 have had a beginning. But the organic world is certainly not 

 eternal and indestructible in that absolute sense in which we 

 apply these terms to matter itself. We can, indeed, kill all organic 

 beings and thus render them inorganic at will. But these changes 

 are not the same as those which we induce in a piece of chalk 

 by pouring sulphuric acid upon it ; in this case we only change 

 the form, and the inorganic matter remains, But when we pour 

 sulphuric acid upon a worm, or when we burn an oak tree, these 

 organisms are not changed into some other animal and tree, but 

 they disappear entirely as organized beings and are resolved into 

 inorganic elements. But that which can be completely resolved 

 into inorganic matter must have also arisen from it, and must 

 owe its ultimate foundation to it. The organic might be con- 

 sidered eternal if we could only destroy its form, but not its nature. 



It therefore follows that the organic world must once have arisen, 

 and further that it will at some time come to an end. Hence we 

 must speak of the eternal duration of unicellular organisms and 

 of reproductive cells in the Metazoa and Metaphyta in that } ar- 

 ticular sense which signifies, when measured by our standards, an 

 immensely long time. 



Yet who can maintain that he has discovered the right answer to 

 this important question? And even though the discovery were 

 made, can any one believe that by its means the problem of life 

 would be solved ? If it were established that spontaneous genera- 

 tion did actually occur, a new question at once arises as to the 

 conditions under which the occurrence became possible. How can 

 we conceive that dead inorganic matter could have come together 

 in such a manner as to form living protoplasm, that wonderful 



