208 REVIEWS. 



the leaves are irritated the current is disturbed in the same 

 manner as takes place during the contraction of the muscle of 

 an animal." The conclusion here needs to be checked by 

 parallel experiments, to see whether the same reversion of 

 current does not take jDlace whenever a part of any leaf or 

 green shoot is forcibly bent upon itself. 



Aldrovanda vesiculosa^ of the Drosera family, "maybe 

 called a miniature aquatic Dionasa ; " for, as discovered by 

 Stein in 1873, " the bilobed leaves open under a sufficiently 

 high temperature, and when touched suddenly close." Being 

 submerged, their prey is confined to minute aquatic animals. 

 For want of proper material and opportunity, Mr. Darwin 

 was able to follow up only for a little way the observations of 

 Stein and Cohn, — enough, however, to show that it also ca2> 

 tures and consumes animals, but perhaps avails itself of the 

 nitrogenous matter only when passing into decay. 



Drosophyllum, a rare representative of the order, confined 

 to Portugal and Morocco, grows on the sides of dry hills near 

 Oporto ; so that, as to station, it is the very counterpart of 

 Aldrovanda. Its leaves are long and slender, in the manner 

 of our Dvosera filiformis., and are covered with much larger 

 glands. To these, flies adhere in vast numbers. " The latter 

 fact is well known to the villagers, who call the plant the 

 ' fly-catcher,' and hang it up in their cottages for this purpose." 

 Mr. Darwin found the glands incapable of movement, and 

 their behavior in some other respects differs from that of 

 Drosera ; but they equally secrete a digestive juice. Insects 

 usually drag off this secretion instead of being fixed on the 

 glands by it ; but their fate is no better ; for as the poor ani- 

 mal crawls on and these viscid drops bedaub it on all sides, it 

 sinks down at length exhausted or dead, and rests on a still 

 more numerous set of small sessile glands which thickly cover 

 the whole surface of the leaf. These were till then dry and 

 inert, but as soon as animal matter thus comes in contact 

 with them, they also secrete a digestive juice, which, as Mr. 

 Darwin demonstrated, has the power of dissolving bits of 

 coagulated albumen, cartilage, or meat, with even greater 

 readiness than that of Drosera. 



