Chap. YI. AIDED BY WORMS. 261 



even on a level field, to leeward, whilst they 

 are soft; and in like manner the pellets 

 when they are dry. If the wind hlows in 

 nearly the direction of an inclined surface, 

 the flowing down of the castings is much 

 aided. 



The observations on which these several 

 statenients are founded must now be given in 

 some detail. Castings when first ejected are 

 viscid and soft ; during rain, at which time 

 worms apparently prefer to eject them, they 

 are still softer ; so that I have sometimes 

 thought that worms must swallow much 

 water at such times. However this may 

 be, rain, even when not very heavy, if 

 long continued, renders recently-ejected 

 castings semi-fluid ; and on level ground 

 they then spread out into thin, circular, flat 

 discs, exactly as would so much honey or 

 very soft mortar, with all traces of their 

 vermiform structure lost. This latter fiict 

 was sometimes made evident, when a worm 

 had subsequently bored through a flat circular 

 disc of this kind, and heaped up a fresh 

 vermiform mass in the centre. These flat 

 subsided discs have been repeatedly seen by 



