158 CONOEENING PRESENT 



believing 'spontaneous generation' to be a chimera, that any 

 apparent success is not simply a case of " survival of germs." 



Still, some may perhaps be inclined to think with me that the 

 balance of evidence is, even here, distinctly in favour of the 

 occurrence of Archebiosis rather than adverse thereto ; although 

 they may also realise that this mode of experimentation with heat- 

 degraded fluids in small vessels cannot in any way be regarded as 

 a fair test of what may now be possible in free nature — that is, 

 with unaltered organic fluids existing under the most favourable 

 conditions. 



There is another point also of great importance which has not 

 previously been referred to, that is, the different ultimate questions 

 left in the two modes by which I have endeavoured to throw 

 light on this question. We found (p. 52) that so far as mere 

 observation goes. Bacteria may be seen in a thin film of suitable 

 fluid under the microscope gradually emerging from the region of 

 the invisible : the question left here is, have they taken origin 

 from pre-existing invisible germs, or have they been formed as 

 ultra-microscopic particles by a synthetic process, followed by 

 growth and visibility. On the other hand, in the experimental trials 

 the Bacteria which appear are always assumed to be developed 

 from visible and well-known germs, such as are produced by the 

 hay Bacillus and are known to be able to resist higher degrees of 

 heat than the organisms in which they have been formed: the 

 question that should be left here is really, with most critics, 

 replaced by an assumption that these known visible germs have been 

 present^ have survived destruction, and have given rise to any new 

 birth of Bacteria that may appear. This assumption, however, 

 covers only part of the ground — not being applicable to Torulae 

 and Fungus germs generally, since in them no highly resistant 

 ' spores ' are known, and de Barry tells us " it has not been shown 

 that any can under these circumstances [that is, in water or watery 

 vapour] survive a temperature of 100° C." The evidence I have 

 adduced, as well as that referred to from Pouchet, is, therefore, 

 altogether in favour of the de novo origin of such forms of life. 



It thus seems as if we have in reality two distinct and more 

 or less independent methods for attacking the problem as to the 

 present occurrence of Archebiosis — that (a) by experiment with 

 superheated fluids in closed flasks, and (6) another less recognised 

 method, that of mere observation, aided by high microscopic 

 powers, of what occurs in thin films of suitable unheated organic 



