CHAPTER III.

ON THE ORIGIN OF FERMENTS PROPERLY SO CALLED.

§ I. On the conditions which cause variations in the nature of the organized products existing in infusions 33

§ II. Experiments on blood and urine taken in their normal state, and exposed to contact with air that has been deprived of the particles of dust which it generally holds in suspension 40

§ III. Experiments on the juice contained in grapes 54

§ IV. Wort and must exposed to common air 59

§ V. New comparative studies on the germs held in suspension by the air of different places which are near each other, but subjected to different conditions affecting the production and diffusion of the particles of dust found in them 72

§ VI. Yeast may become dry and be reduced to dust without losing its faculty of reproduction 81