SPONTANEOUS GENERATION. 131 



teems with a life invisible except to the higher powers of the 

 microscope — a life which reproduces itself by the ordinary 

 and natural methods, and which is ever on the alert to catch 

 the first opportunity of springing into active instead of po- 

 tential vitality. 



It is not necessary here to enter upon the experimental 

 evidence upon this subject. Upon no single question, pro- 

 bably, in the whole range of Biology, have greater pains been 

 expended, and more elaborate experiments carried out ; and 

 upon no single question have the actual results of the inquiry 

 been so singularly contradictory and unsatisfactory. All the 

 experiments which have been set on foot with a view of 

 settling this question have been directed to one of two ends 

 — ^viz., to prove that no life would appear in organic infu- 

 sions from which germs were rigidly excluded, or to. show 

 that living organisms appeared in fluids in which it was im- 

 possible that any germs could be present. Neither end has 

 as yet been satisfactorily attained ; and from the nature of 

 the case it is difficult to believe that the experimental evi- 

 dence could, under any circumstances, ever amount to 

 actual demonstration. For our present purpose it will be 

 sufficient, very briefly, to consider some recent experiments 

 carried out by Dr Charlton Bastian with a view of proving 

 the occurrence of Abiogenesis. 



The most important experiments carried out by this ob- 

 server consisted in taking an organic infusion — such as an 

 infusion of turnip — boiling it, to expel the air as far as pos- 

 sible, as well as to kill any germs which might be present in 

 the fluid, and then hermetically sealing the neck of the flask 

 in the flame of a spirit-lamp. By this procedure it will be 

 at once evident that the experimenter had an infusion con- 

 taining dead organic matter, but ostensibly containing no 

 living germs, enclosed in a flask from which all, or nearly 

 all, the atmospheric air had. been expelled by boiling. The 

 flask thus prepared was submitted for hours to a tempera- 

 ture considerably over the boiling-point of water, and then 



