Cellulase is an adaptive enzyme in most fungi (Reese and Levinson, 1952), although it is constitutive in cellulolytic bacteria (Hammerstrom et al., 1955). Many polysaccharases are adaptive in fungi, including: pentosanase (Simpson, 1954), polygalacturonase (Phaff, 1947), chitinase (Reynolds, 1954), dextranase (Hultin and Nordstr6m, 1949), and xylanase and mannanase (S0rensen, 1952). Since many ...