PLANT NUTRITION. 33 



the supply of oxygen to the ferment, in consequence of 

 which the glucose they contain becomes converted into 

 alcohol. 



Carnivorous Plants, Parasites, The leaves of certain 

 plants are endowed under certain circumstances with a 

 power of digesting and absorbing animal substances 

 placed in contact with them. When a minute fragment 

 of meat, for instance, is placed upon the leaf of a drosera, 

 or sundew, the tentacle-like glandular hairs of the plant 

 bend over to grasp the intruding morsel, a peculiar di- 

 gestive fluid is formed as a result of the contact just as 

 the gastric juice in the human stomach is secreted when 

 food enters that organ and this fluid effects the solution 

 of the meat, the nutritive solution so formed being 

 absorbed and applied to the benefit of the plant. To 

 common observation the actual gain to the plant by this 

 method of feeding may appear slight, or even none ; but 

 the more delicate tests applied by the botanist have 

 sufficed to prove, not only that the processes just 

 mentioned really do go on, but also that they are ben- 

 eficial to the plant, and contribute to the formation of 

 more numerous and more robust seedlings. The ration- 

 ale of this mode of obtaining nutrition seems somewhat 

 analogous to that in the root, where also the acid fluid 

 with which the cell-wall is permeated, when it comes 

 into contact with the particles of soil, determines their 

 solution and renders them fit for absorption into the 

 plant. Practically this admittedly exceptional mode of 

 nutrition by the leaf might seem of little moment, but it 

 is probable that in the future direct nutrition by this 

 means will be shown to be of much greater importance 

 than it appears to be at present. In any case, the fact 

 that ammonia-solutions and ammonia-vapors are absorbed 

 by leaves with increased manifestations of vital activity, 

 renders this mode of feeding a matter of some conse- 



