Note 154 — Chapter VI · THE PHYSIOLOGICAL THEORY OF FERMENTATION. (continued 2)

“There are two classes of ferments; the first, of which the yeast of beer may be taken as the type, perpetuate and renew themselves if they can find in the liquid in which they produce fermentation food enough for their wants; the second, of which diastase is the type, always sacrifice themselves in the exercise of their activity.” (Dumas, Comptes rendus de l’Académie, t. lxxv. p. 277, 1872.)