150 THE FLOATING-MATTER OF THE AIR. 



the influence of drying and hardening* was brought home 

 to me by the fact that in all the foregoing cases the 

 infusions which five minutes' boiling proved sufficient 

 to sterilize were, ivithout exception, derived from fresh 

 hay mown in 1876, while the infusions which five 

 minutes^ boiling failed to sterilize ivere derived, luith- 

 out exception, from old hay mown either in 1875 or 

 some previous year. 



In the earlier experiments of the present inquiry 

 this distinction between old and new hay came most 

 clearly and definitely out. The result was subsequently 

 blurred by circumstances which it required time and 

 labour to unravel, and which will require patience on 

 the reader's part if he would thoroughly follow them. 

 They will, however, throw far more light upon the real 

 character of these inquiries, and do more to reconcile 

 the discords to which researches on spontaneous genera- 

 tion have given birth, than if every experiment had 

 been a success unshaded by doubt. 



§ 7. Hay-infusions. Further experiments with 

 Closed Chambers. 



With a view to probing to the uttermost this ques- 

 tion of drying and hardening, on the 6th of October 

 an extensive series of experimc nts with closed chambers 

 was begun. Three different kinds of hay were em- 

 ployed : — 1 st, Old hay, sent to me by Lord Claud 

 Hamilton, from Heathfield, Sussex ; ' 2nd, new hay 

 from Heathfield (both, it may be stated, from a some- 

 what ungenerous soil) ; 3rd, new hay purchased in 

 London, and artificially dried for some days upon a sand- 



' After the possible influence of bard drying and hardening had 

 suggested itself, I purposely introduced old hay from various locali- 

 ties into the laboratory. 



