PREFACE. xi 



those cases where only a few organisms exist in 

 a solution which has been made the subject of 

 experimentation, nothing is easier than by a per- 

 functory examination of the fluid to fail in finding 

 any of these sparsely-distributed living organisms. 

 Experiments, the results of which are positive, 

 may, therefore, in the absence of sufficient care, 

 be cited as negative ; and experiments which 

 would otherwise have been crowned with tmmis- 

 takeably positive results, may be rendered wholly 

 barren by the employment of infusions which have 

 been carelessly made. 



A word of explanation seems necessary with 

 regard to the introduction of the new term 

 Archebiosis. I had originally, in unpublished writ- 

 ings, adopted the word Biogenesis to express 

 the same meaning - - viz., life-origination or com- 

 mencement. But in the mean time the word Bio- 

 genesis has been made use of, quite independently, 

 by a distinguished biologist, who wished to make 

 it bear a totally different meaning. He also intro- 

 duced the word A biogenesis. I have been informed, 

 however, on the best authority, that neither of these 

 words can with any regard to the language from 

 which they are derived be supposed to bear the 

 meanings which have of late been publicly assigned 



b 



