Plants That Feed on Insects. 19 



nitrogeneous matter in a soluble condition, as bits of cork, 

 wood, moss for examples, or bodies containing soluble nitro- 

 geneous matter, if perfectly dry, such as small pieces of meat, 

 albumen, gelatine, etc., may be long left on the lobes, and no 

 movement is excited. But when nitrogeneous organic bodies, 

 which are all damp, are left on the lobes, the result is widely 

 different, for these then close by a slow and gradual move- 

 ment and not in a rapid*manner as when one of the sensitive 

 filaments is touched by a hard substance. Small purplish, 

 almost sessile glands, as has already been stated, thickly 

 cover the upper surface of the lobes. These have the power 

 both of secretion and absorption, but they do not secrete 

 until excited by the absorption of nitrogeneous matter. No 

 other excitement, as far as experiments show, produces this 

 effect. When the lobes are made to close over a bit of meat 

 or an insect, the glands over the entire surface of the leaf 

 emit a copious discharge, as in this case the glands on both 

 sides are pressed against the meat or insect, the secretion 

 being twice as great as when the one or the other is laid on 

 the surface of a single lobe ; and as the two lobes come into 

 almost close contact the secretion, containing dissolved ani- 

 mal matter, diffuses itself by capillary attraction, causing 

 fresh glands on both sides to begin secreting in a continually 

 widening circle. The secretion is almost colorless, slightly 

 mucilaginous, moderately acid, and so copious at times in 

 the furrow over the mid-rib as to trickle down to the earth. 

 But all this secretion is for the purposes of digestion. Be 

 the animal matter which the enclosed object yields ever so 

 little, it serves as a peptogene, and the glands on the surface 

 of the leaf pour forth their acid discharge, which acts like 

 the gastric juice of animals. 



Now as to the manner in which insects are caught by the 

 leaves of Dioncea muscipula. In its native country they are 

 caught in large numbers, but whether they are attracted in 

 any special way no one seems to know. Both lobes close 

 with astonishing quickness as soon as a filament is touched, 



