162 The Romance of Wild Flowers 
bend over. It is not easy to mentally estimate the 
smallness of that cotton particle, but what idea can be 
gained of the size of a snippet of hair which weighed 
only sooth part of a grain! Yet this inconceivably 
small portion of animal matter was equally effective 
in setting up the necessary irritation. 
Such inorganic substances as are needed by plants 
as food, and such as they are capable of assimilating, 
do effect inflection of the tentacles and the ag- 
gregation of the protoplasm within. Mr. Darwin 
experimented with the salts of ammonia, and found 
them to have a powerful effect on the glands, causing 
inflection of the tentacles and aggregation of the 
protoplasm. The figures used above for cotton and 
hair appear huge, wholesale quantities when com- 
pared with some of the figures denoting the amounts 
of ammonia found sufficient to cause similar demon- 
strations of sensibility in the tentacles. Of carbonate 
of ammonia gyegoath of a grain was needed, but 
with nitrate of ammonia ;57s9,th was sufficient, 
whilst of the phosphate of ammonia the moderate 
These figures have only an indirect connection 
with the natural history of the plant, and are only 
mentioned to show the marvellous degree of sen- 
sitiveness possessed by the leaves, which have a 
curiously close resemblance in form and action to the 
Sea Anemones of our coasts. In nature the Sundew 
is concerned in catching and digesting small flies and 
beetles, and it is almost an impossibility to find a 
plant that does not bear proof of this fact in the 
majority of its leaves. Here the leaf is newly closed 
upon the victim, there the tentacles have returned to 
