6+6 THE POPULAR SCIENCE MONTHLY. 



cucuinber-infusion was introduced into tlie chamber, and it was found 

 that the superheating of the infusion did not even retard the develoj)- 

 nient of life. In two days every tube of the chamber was swarming 

 with bacteria. I then passed on to another system of experiment 

 pursued last year, that is, the exposure- of the infusions to air calcined 

 by passing a voltaic current through platina-wire, so as to raise the 

 wire to a state of incandescence. Such arrangements are here. We 

 have underneath this shade two wires, and stretching from wire to 

 wire we have a spiral of platinum. Passing a voltaic current through 

 the spiral, it was found last year that five minutes of incandescence 

 were sufficient entirely to sterilize and destroy all germs contained in 

 this air, and to protect the infusions underneath from all contamina- 

 tion; the time of incandescence was doubled this year. The wire 

 was raised as close to the point of fusion as possible; still, notwith- 

 standing all this additional care, the infusions one and all gave way. 

 I thought that there might be some defect in the construction of the 

 apparatus. Here, you see, is an old broken apparatus containing in- 

 fusions that have remained perfectly good since last year ; but great 

 pains were taken in having the apparatus of the most improved form. 

 Still, notwithstanding all my efforts, the infusions broke clown and 

 became swarming with life. My attention was now very keenly 

 arrested, and on December 1st I scrutinized more closely than ever 

 I had done previously the entry of the infusions through the pipette- 

 tube into the tubes opening into the chamber, and I noticed, at all 

 events, a danger of minute air-bubbles being carried down along with 

 the descending infusion. That caused me to adoj)t another mode of 

 experiment; but, previously to this, I fell back upon some of the in- 

 fusions found so easy to sterilize the previous year. I operated upon 

 beef, mutton, pork, and herring infusions, and found that even such 

 infusions, which with the most ordinary care were completely sterilized 

 last year, and are preserved to the present hour intact like the others, 

 all gave w r ay. 



How, then, are we to look at these things? Here are results 

 totally different from those that w T e obtained last year. You may ask 

 me, perhaps : " Why do you not loyally bow to the logic of facts and 

 accept the conclusion to which those experiments apparently so clearly 

 point? Why do you not regard them as a demonstration of the doc- 

 trine of spontaneous generation? Is there any other way of account- 

 ing for it than by a reference to this doctrine?" You may ask 

 whether I was held back by prejudice from accepting this conclusion, 

 whether I was held back by a love of consistency, or by the fear, of 

 being turned into ridicule and sneered at by those whom I ventured 

 to oppose on a former occasion. Ladies and gentlemen, there is a 

 title which I believe, as the generations pass, will, if the owners of 

 the title arc true to themselves, become more and more a title of 

 honor that is, the title of a man of science and of that title I should 



