VI PREFACE. 



although at first wishing to do this in a work much 

 smaller than that which I now submit to the public, it 

 was soon found that more elaboration would be needed. 

 The scope of the subject itself, moreover, widened so 

 rapidly biological problems of such enormous import- 

 ance were opened up that I at last felt compelled to 

 pursue the investigation in a manner a little more com- 

 mensurate with the magnitude of its dependent issues. 



The First Part of this work was written and printed 

 nearly three years ago. It was intended to show the 

 general reader, more especially, that the logical conse- 

 quences of the now commonly accepted doctrines con- 

 cerning the c Conservation of Energy' and the c Cor- 

 relation of the Vital and Physical Forces,' were wholly 

 favourable to the possibility of the independent origin 

 of c living ' matter. It also contains a review of the 

 c Cellular Theory of Organization/ which was written 

 and was in type before I had had the pleasure of reading 

 Prof. Strieker's essay on c Cells.' 



In the Second Part of the work, under the head 

 c Archebiosis/ the question as to the present occurrence 

 or non-occurrence of < spontaneous generation ' is fully 

 considered. And in spite of all the difficulties in 

 great part imaginary which have hitherto interfered 

 with the acceptance of a positive solution of this 

 problem, it seems to me one which is now not difficult 

 to solve. It must be considered to turn almost wholly 

 upon the possibility of the de novo origin of Bacteria ; 

 since if such a mode of origin can be proved for them, 

 it must also be conceded for other allied fungoid and 

 algoid units. Evidence which is of the most convincing 

 character when looked at from all sides, now shows 



