350 PEESONAL RECOLLECTIONS OF 



came to an end in 1867, on Hampton Court Green, 

 Eeverently, but reluctantly, I took his place as Super- 

 intendent of the Eoyal Institution, vastly preferring, 

 if it could have been so arranged, to leave Mrs. Fara- 

 day in undisturbed possession of the rooms which had 

 been her happy home for six-and-forty years. The 

 thing, however, could not be. On returning from one 

 of my Alpine expeditions I found at the entrance of 

 the place which had been occupied successively by 

 Davy and Faraday, my name upon the wall. It was 

 to me more of a shock than a satisfaction. 



The change, however, brought me nearer to Carlyle; 

 and to Albemarle Street from time to time he wended 

 his way to see me. Once he found me occupied, not 

 with a problem of physics, but with a question of biology 

 of fundamental import. The origin of life was, is, and 

 ever will be, a question of profoundest interest to 

 thoughtful men. In the early ' seventies ' I was busy 

 experimenting on this question, my desire being to 

 bring to bear upon it physical methods which should 

 make known the unmistakable verdict of science re- 

 garding it, and thus abolish the doubt and confusion 

 then existing. Permitting air to purify itself by the 

 subsidence of all floating motes, so that the track 

 through it of a sunbeam, even when powerfully concen- 

 trated, was invisible, infusions of meat, fish, fowl, and 

 vegetables were exposed to such air and found inca- 

 pable of putrefaction. The vital oxygen was still there; 

 but with the floating motes, the seminal matter of the 

 atmosphere had vanished, and with it the power of 

 generating putrefactive organisms. The organisms, in 

 other words, required the antecedent seed — there was 

 no spontaneous generation. By means of gas stoves 

 rooms had been raised to the proper temperature, and 

 into one of these rooms, which was stocked with m^ 



