338 DROSOPHYLLUM LUSITANICUM. Chap. XV. 



pedicels and to tlie minute sessile ones. Before a 

 gland lias been in any way stimulated, the exterior cells 

 commonly contain only limpid purple fluid ; the more 

 central ones including mulberry-like masses of purple 

 granular matter. A leaf was placed in a little solution 

 of one part of carbonate of ammonia to 146 of water (3 

 grs. to 1 oz.), and the glands were instantly darkened 

 and very soon became black ; this change being due 

 to the strongly marked aggregation of their contents, 

 more especially of the inner cells. Another leaf was 

 placed in a solution of the same strength of nitrate of 

 ammonia, and the glands were slightly darkened in 

 25 m., more so in 50 m., and after 1 hr. 30 m. were of 

 so dark a red as to appear almost black. Other leaves 

 were placed in a weak infusion of raw meat and in 

 human saliva, and the glands were much darkened in 

 25 m., and after 40 m. were so dark as almost to 

 deserve to be called black. Even immersion for a 

 whole day in distilled water occasionally induces some 

 aggregation within the glands, so that they become of 

 a darker tint. In . all these cases the glands are 

 affected in exactly the same manner as those of 

 Drosera. Milk, however, which acts so energetically 

 on Drosera, seems rather less effective on Droso- 

 phyllum, for the glands were only slightly darkened 

 by an immersion of 1 h^;. 20 m., but became decidedly 

 darker after 3 hrs. Leaves which had been left for 

 7 hrs. in an infusion of raw meat or in saliva were 

 placed in the solution of carbonate of ammonia, and 

 the glands now became greenish; whereas, if they 

 had been first placed in the carbonate, they would 

 have become black. In this latter case, the ammonia 

 probably combines with the acid of the secretion, 

 and therefore does not act on the colouring matter ; 

 but when the glands are first subjected to an organic 



