STUDIES ON FERMENTATION. 99 



microscopic organisms exist abundantly on the surface of all 

 fruits. 



Having impregnated the liquids in our flasks with spores 

 from a quantity of pure sporangia grown in a closed vessel, 

 gathered on the point of a platinum wire, which had first been 

 heated and then allowed to cool, we found that in each ease, 

 without exception, germination took place, then a mycelium was 

 developed, which soon, however, ceased to grow from want of 

 a proper supply of air ; but not in any single case was there the 

 faintest trace of fermentation, formation of yeast, or appearance 

 of bacteria or lactic ferment. 



We repeated these experiments, using unhopped wort instead 

 and obtained similar negative results. We had previousljr 

 determined that it was necessary to heat flasks of hopped 

 wort to 70° C (158° F.), at least, and those of unhopped wort to 

 90° C, (194° F.) to secure them from further change. 



In short, contrary to the assertions of M. Trecul, M. H. 

 Hoflfmann, and other naturalists, it is not true that the spores of 

 2)eniciUium can change into alcoholic ferment. 



Regarded from another point of view, growths of pure 

 penicillium will give us some remarkable results, the interpreta- 

 tion of which seems to us to be intimately connected with the 

 physiological theory of fermentation that we shall discuss in a 

 subsequent chapter. It is a question as to the production of 

 alcohol whilst the life of the plant is carried on under certain 

 conditions of growth. 



If we distil saccharine liquids on the surface or in the body 

 of which we have grown penicillium, and repeat the distillation 

 in the manner that we have already described for the detection 

 of the minutest quantities of alcohol, we shall readily find that 

 those liquids frequently do contain a little ordinary alcohol. 

 Moreover, if we regard the quantities of alcohol produced, 

 which are always very minute, seldom exceeding 1 or 1'5 

 thousandth of the total volume of the liquids, we shall find 

 that there is no fixed proportion between this alcohol and the 

 weights of the plants formed. It is possible, for instance, that 



H 2 



