be left for a length of time on the surface of a leaf, and it remains quite dry.  Nor does it make any difference if the lobes close over such objects.  For instance, some little balls of blotting paper were placed on a leaf, and a filament was touched; and when after 24 hrs. the lobes began to re-open, the balls were removed by the aid of thin pincers, and were found perfectly dry.  On the other hand, if a bit of damp meat or a crushed fly is placed on the surface of an expanded leaf, the glands after a time secrete freely.  In one such case there was a little secretion directly beneath the meat in 4 hrs.; and after an additional 3 hrs. there was a considerable quantity both under and close round it.  In another case, after 3 hrs. 40 m., the bit of meat was quite wet.  But none of the glands secreted, excepting those which actually touched the meat or the secretion containing dissolved animal matter.

If, however, the lobes are made to close over a bit of meat or an insect, the result is different, for the glands over the whole surface of the leaf now secrete copiously. [page 296] As in this case the glands on both sides are pressed against the meat or insect, the secretion from the first is twice as great as when a bit of meat is laid on the surface of one lobe; and as the two lobes come into almost close contact, the secretion, containing dissolved animal matter, spreads by capillary attraction, causing fresh glands on both sides to begin secreting in a continually widening circle.  The secretion is almost colourless, slightly mucilaginous, and, judging by the manner in which it coloured litmus paper, more strongly acid than that of Drosera.  It is so copious that on one occasion, when a leaf was cut open, on which a small cube of albumen had been placed 45 hrs. before, drops rolled off the leaf.  On another occasion, in which a leaf with an enclosed bit of roast meat spontaneously opened after eight days, there was so much secretion in the furrow over the midrib that it trickled down.  A large crushed fly (Tipula) was placed on a leaf from which a small portion at the base of one lobe had previously been cut away, so that an opening was left; and through this, the secretion continued to run down the footstalk during nine days,—­that is, for as long a time as it was observed.  By forcing up one of the lobes, I was able to see some distance between them, and all the glands within sight were secreting freely.

We have seen that inorganic and non-nitrogenous objects placed on the leaves do not excite any movement; but nitrogenous bodies, if in the least degree damp, cause after several hours the lobes to close slowly.  Thus bits of quite dry meat and gelatine were placed at opposite ends of the same leaf, and in the course of 24 hrs. excited neither secretion nor movement.  They were then dipped in water, their surfaces dried on blotting paper, and replaced on the same [page 297] leaf, the plant being now covered with a bell-glass.