SPONTANEOUS GENERATION. 599 



of Dr. Bastian, uttered not in a popular book, but in the "Proceedings 

 of the Royal Society," ' with reference to this very experiment : " We 

 can only infer that while the boiled saline solution is quite incapable 

 of engendering bacteria, such organisms are able to arise de novo in 

 the boiled organic infusion." I would ask my eminent colleague what 

 he thinks of this reasoning now ? The datum is, " A mineral solu- 

 tion exposed to common air does not develop bacteria : " the infer- 

 ence is, "Therefore, if a turnip-infusion similarly exposed develop 

 bacteria, they must be spontaneously generated." The inference, on 

 the face of it, is an unwarranted one. But, while as matter of logic it 

 is inconclusive, as matter of fact it is chimerical. London air is as 

 surely charged with the germs of bacteria as London chimneys are 

 with smoke. The inference just referred to is completely disposed of 

 by the simple question: " Why, when your sterilized organic infusion 

 is exposed to optically pure air, should this generation of life de novo 

 utterly cease ? Why should I be able to preserve my turnip-juice 

 side by side with your saline solution for the three hundred and sixty- 

 five days of the year, in free connection with the general atmosphere, 

 on the sole condition that the portion of that atmosphere in contact 

 with the juice shall be visibly free from floating dust, while three 

 days' exposure to that dust fills it with bacteria?" Am I over-san- 

 guine in hoping that, as regards the argument here set forth, he who 

 runs may read, and he who reads may understand ? Let me add, 

 however, that while exposing the fallacy of the inferences drawn from 

 it, I regard the observation that the boiled saline solution can sustain 

 the developed organisms, while it cannot develop them from the dry 

 germinal matter of the air, as an important addition to our knowledge. 

 We are indebted for it to Dr. Burdon-Sanderson, who soon saw that 

 his first interpretation of it went too far, and who, in a communication 

 recently presented to the Royal Society, abandons the interpretation 

 altogether. 



We now proceed to the calm and thorough consideration of another 

 subject, more important if possible than the foregoing one, but like 

 it somewhat difficult to seize by reason of the very opulence of the 

 phraseology, logical and rhetorical, in which it has been set forth. 

 The subject now to be considered relates to what has been called "the 

 death-point of bacteria." Those who happen to be acquainted with 

 the modern English literature of the question will remember how 

 challenge after challenge has been issued to panspermatists in general, 

 and to one or two home workers in particular, to come to close quar- 

 ters on this cardinal point. It is obviously the stronghold of the 

 English heterogenist. " Water," he says, " is boiling merrily over a 

 fire, when some luckless person upsets the vessel so that the heated 

 fluid exercises its scathing influence upon an uncovered portion of the 

 body hand, arm, or face. Here at all events there is no room for 



1 Vol. xxi., p. 130. 



