THE SUNDEWS — continued. 
secretion is neutral until it has captured some nitrogenous body, when it becomes 
acid and contains at least one digestive ferment or enzyme. As the secretion is 
then capable of digesting both nitrogenous matters, as does the pepsin of the animal 
stomach, and starchy substances, as does the ptyalin of saliva, it would seem that 
either two special ferments are present or that there is one with the double function 
like that of the pancreas in the higher animals. The tentacles are extremely sensitive 
to contact with the most minute particles of organic matter, bending at their bases 
(sometimes through i8o°) so as to carry the captured fly or other body to the 
centre of the leaf. Nor is the change in the character of the secretion and this 
movement confined to the tentacle that captures the prey. The protoplasm of the 
cells of this tentacle contracts and breaks up into rounded masses, and this change 
spreads rapidly from cell to cell throughout the leaf, all the glands in turn becoming 
acid and all the tentacles bending inwards. It has been experimentally demonstrated 
that the plants benefit, both in vegetative growth and in the production of flower, 
fruit, and seed, by this method of nutrition ; and possibly the reddish colouring 
which largely replaces their chlorophyll may be an indication of their comparative 
independence of atmospheric carbon-dioxide. 
As the two remaining genera in the Family — the Venus’s Fly-trap {Dionaa 
muscipula Ellis) of the south-eastern United States, and the rootless aquatic 
Aldrovanda of Australia, India, and Southern Europe, though more elaborately 
organised — have fewer species and a less wide distribution, Darwin truly says that 
“ Drosera has been incomparably the most successful in the battle of life.” 
In our British species the flowers are cleistogamous, just showing the white 
petals but not opening, so that they are necessarily self-pollinating. 
The popular name Sundew is probably from the Teutonic sindau^ meaning ever- 
dewy, though it has long been misinterpreted so as to become the German 
Sonnenthau and the Ros solis of mediaeval pharmacy, which was further corrupted 
into Rosa solis. 
Burton in his “ Anatomy of Melancholy ” quotes Bernardus Penottus, a 
mediaeval physician of Salerno, as saying that “ for all ills and phantasies of the 
head no herb upon earth is comparable to this herha solis." 
