270 DROSERA ROTUNDIFOLIA. Cuap. XI 
of the seedlings. It also absorbs matter from pollen, 
and from fragments of leaves. 
The seventh chapter was devoted to the action of 
the salts of ammonia. These all cause the tentacles, 
and often the blade of the leaf, to be inflected, and 
the protoplasm to be aggregated. They act with very 
different power; the citrate being the least powerful, 
and the phosphate, owing, no doubt, to the presence 
of phosphorus and nitrogen, by far the most powerful. 
But the relative efficiency of only three salts of 
ammonia was carefully determined, numely the car- 
bonate, nitrate, and phosphate. The experiments were 
made by placing half-minims (0296 ml.) of solutions 
of different strengths on the discs of the leaves,—by 
applying a minute drop (about the j; of a minim, or 
00296 ml.) for a few seconds to three or four glands,— 
and by the immersion of whole leaves in a measured 
quantity. In relation to these experiments it was 
necessary first to ascertain the effects of distilled water, 
and it was found, as described in detail, that the more 
sensitive leaves are affected by it, but only in a slight 
degree. 
A solution of the carbonate is absorbed by the roots 
and induces aggregation in their cells, but does not 
affect the leaves. The vapour is absorbed by the 
glands, and causes inflection as well as aggregation. 
A drop of a solution containing 54, of a grain 
(0675 mg.) is the least quantity which, when placed 
on the glands of the disc, excites the exterior ten- 
tacles to bend inwards. But a minute drop, contain- 
ing +s4s7 of a grain (‘00445 mg.), if applied for a few 
seconds to the secretion surrounding a gland, causes 
the inflection of the same tentacle. When a highly 
sensitive leaf is immersed in a solution, and there is 
ample time for absorption, the ayyso5 of a grain 
