8PONTANK XRRATION. 



mentors eoually skillful ami tonally careful, operating in 

 different places on B infusion, in the same wa\ 



assuming the obtain life while tin- ..ther fails to 



i it; then its well-established absence in the one case 

 .t some ingredient foreign to the infusion must 

 be its cause in the other. 



lan/ani's sealed flasks contained but small quantities 

 of air. ...\ygen was afterward shown to he generally 



essential to life, it was thought that the absence of life 

 observed hy Spallanzani might have been due to the lack of 



, r gas. To dis-ipate this doubt. Sdmi 

 naif tilled a flask with distilled water to which animal 

 ami \ matters were added. First boiling his infu- 



sion to destroy whatever life it might contain, Schiilze 



1 daily into his tlask air which has passed t lin- 

 geries of bulbs containing concentrat -d sulphuric acid, 

 where all germs of life suspended in the air were suppose) 

 to be destroyed. From May to August this process was 

 continued without any development of infusorial life. 



11 n au'.-i'n: the success of Schulze was due to his work- 

 ing in comparatively pure air, but even in such air his 

 experiment is a very risky one. Germs will pass un wetted 

 and unscathed through sulphuric acid unless the most 

 special care is taken to detain them. I have repeatedly 

 failed, by repeating Schulze's experiments, to obtain his 

 results. Others have failed likewise. The air pa- 

 bubbles through the bulbs, and to render the method 

 secure, the passage of the air must be so slow as to cause 

 the whole of its floating matter, even to the very core of 

 each bubble, to touch the surrounding liquid. Hut if this 

 precaution be observed, water will be found quite as effect- 

 ual as sulphuric acid. Hy the aid of an air-pump in a 

 highly infective atmosphere I have thus drawn air for 

 weeks without intermission, first through bulbs containing 

 water, and afterward through vessels containin 

 infusions, without any appearance of life. T 

 were not killed by the water, hut they were effectually in- 

 tercepted, while the objection that the air had been injured 

 by being brought into contact with strongly corrosive 

 substances was avoided. 



hri.-f paper of Schulze, puhli-dn-d in ' i.n-f's 



1836, was followed i 

 and pregnant communicat i<m 1,\ Sohwftan, Ucdi, as we 



