CHAP. I. FOOD AND DIGESTION. 39 



secretion of the higher animals, are acted on 

 by that from the pancreas.* 



The half-decayed or fresh leaves which 

 worms intend to devour, are dragged into the 

 mouths of their burrows to a depth of from 

 cne to three inches, and are then moistened 

 with a secreted fluid. It has been assumed 

 that this fluid serves to hasten their decay ; 

 but a large number of leaves were twice 

 pulled out of the burrows of worms and kept 

 for many weeks in a very moist atmosphere 

 under a bell-glass in my study ; and the parts 

 which had been moistened by the worms did 

 not decay more quickly in any plain manner 

 than the other parts. When fresh leaves 

 were given in the evening to worms kept in 

 confinement and examined early on the next 

 morning, therefore not many hours after they 

 had been dragged into the burrows, the fluid 

 with which they were moistened, when tested 

 with neutral litmus paper, showed an alkaline 

 reaction. This was repeatedly found to be 

 the case with celery, cabbage and turnip 

 leaves. Parts of the same leaves which had 



* Schmulewitsch, ' Action des Sues digestifs sur la Cellulose.' 

 Bull, de 1'Acad. Imp. de St. Petersbourg, torn. xxv. p. 549. 1879. 



