THE GENESIS OF LIFE. 179 



Clear hay infusions allowed to stand for months could be 

 inoculated with specks of liquid containing bacteria, and 

 then were observed, as every one would have expected, to 

 develop abundance of life. In the autumn of 1876 the 

 experiments on hay began, curiously enough, to afford widely 

 different results from those just detailed ; the infusions 

 being ultimately found to withstand boiling with impunity, 

 as far as rendering them sterile was concerned, for fifteen 

 minutes. Pursuing the inquiry, Professor Tyndall ascer- 

 tained that the hay infusions which resisted sterilisation by 

 boiling were made from old hay ; solutions made from new 

 hay being readily sterilised. Further experimentation on 

 infusions of substances, such as fish and flesh, which formerly 

 had been successfully and readily rendered barren by ex- 

 posure to heat, showed that these latter materials also 

 exhibited an unwonted resistance to high temperatures. So 

 that the experimenter was led to conclude that "either the 

 infusions of fish, flesh, and vegetable had become endowed 

 in 1876 with an inherent generative energy which they did 

 not possess in 1875, or some new contagium external to the 

 infusions, and of a far more obstinate character than that 

 of 1875, had been brought to bear upon them." These 

 words are pregnant with meaning, and suggest forcibly that 

 the moods and tenses of organic matters on the one hand, 

 and of the atmosphere and its particles on the other, are 

 probably of very varied character, and tend to complicate 

 exceedingly the question of life-genesis. 



Shifting his camp from London to Kew, Professor Tyn- 

 dall found that the infusions which resisted sterilisation in 

 the former place were sterilised with all their former readi- 

 ness at Kew. And experiment carried on in a specially 

 constructed chamber in London resulted in failures as far as 

 sterilisation was concerned, until due precautions were taken 

 to prevent infective influences being imported into the 

 chamber. Highly interesting is it to find a feasible cause 

 for the infection of the air of the London laboratory in the 

 presence of fine dust arising from bundles of old and very 



