DIGESTION AND METABOLISM 



21 



Considerable quantities of plant material are included in the 

 food of earthworms, of course, and enzymes capable of utilizing 

 the cellulose of these plants would be of considerable value. As we 

 have seen. Lesser and Taschenberg (1908) suggested that cellulase 

 is present, and this has been confirmed by Tracey (1951). At a 

 pH of 5 the viscosity of solutions of sodium carboxy-methyl- 



0-6 

 0-5 



0-4 



e 0-3 

 0-2 

 0-1 



0-8 

 0-7 

 0-6 

 0-5 



0'4 

 0'3 

 0-2 



0-i 



Nornnaltiere: 



Li 



T RW T RW T RW T RW 



20-40 40-60 segment 20- 40 40-60 

 ph: 5-6- 5-7 ph: 7-7- 7-8 



:.J 



Hungertiere: 



'^, 



T RW T RW r RW T RW 



20-40 40-60 segment 20-40 40-60 

 ph 5-5 ph:7-6 



Fig. 8. Protease activity of gut of L. terrestris. Above, normal 

 animals, below, starved animals, e — measure of activity; T = 

 typhlosole; RW = remainder of gut wall in segments 20-40, 

 40-60. Experiments run at pH indicated (from Heran, 1956). 



cellulose is lowered by extracts of the anterior half of the intestine. 

 This is presumptive evidence for the presence of cellulase, and 

 further evidence is provided by the fact that incubation of finely 

 powdered cellulose with gut extracts is followed by the appearance 

 of soluble reducing sugars in the reaction mixture. 



Tracey (1951) also found that acetyl glucosamine is produced as 



