352 ON THE NATURE OF FERMENTATION 
insist on; but what I do venture to urge upon you is, that you will seriously 
ponder over the facts which I have had the honour of bringing before you to-day; 
and, if you do so, I believe you will agree with me that we have absolute 
evidence that the Bacterium lactis is the cause of the lactic-acid fermentation. 
And thus I venture to believe that we have taken one sure step in the way 
of removing this important but most difficult question from the region of 
vague speculation and loose statement into the domain of precise and definite 
knowledge. 
