Cuar. XIII] DIGESTION. 243 
infusion of raw meat, to see whether they absorbed tho 
vapour, but their contents were not affected. 
Digestive Power of the Secretion.*—-When a leaf closes over 
any object, it may be said to form itself into a temporary 
stomach; and if the object yields ever so little animal 
matter, this serves, to use Schiff’s expression, as a peptogene, { 
and the glands on the surface pour forth their acid secretion, 
which acts like the gastric juice of animals. As so many ex- 
periments were tried on the digestive power of Drosera, only 
a few were made with Dionea, but they were amply sufficieut 
to prove that it digests. This plant, moreover, is not so 
* Dr. W. M. Canby, of Wilmington, 
to whom I am much indebted for 
information regarding Dionza in its 
native home, has published in the 
‘Gardener’s Monthly,’ Philadelphia, 
August 1868, some interesting ob- 
servations. He ascertained that the 
secretion digests animal matter, such 
as the contents of insects, bits of 
meat, &c.; and that the secretion is 
reabsorbed. He was also well aware 
that the lobes remain closed for a 
much longer time when in contact 
with animal matter than when made 
to shut by a mere touch, or over 
objects not yielding soluble nutri- 
ment; and that in these latter cases 
the glands do not secrete. The Rev. 
Dr. Curtis first observed (‘ Boston 
Journal Nat. Hist.’ vol. i. p. 123) 
the secretion from the glands. I 
may here add that a gardener, Mr. 
Knight, is said (Kirby and Spence’s 
‘Introduction to Entomology,’ 1818, 
vol. i. p. 295) to have found that a 
plant of the Dionxa, on the leaves of 
which “ he laid fine filaments of raw 
beef, was much more luxuriant in its 
growth than others not so treated.” 
(The earlier history of the subject 
is given in Sir Joseph Hooker’s “ Ad- 
dress to the Department of Botany 
and Zoology,” ‘British Association 
Report,’ 1874, p. 102, whence the 
following facts are taken. 
About 1768 Ellis, a well-known 
English naturalist, sent to Linneus a 
drawing and specimens of Dionza 
with the following remarks (“A Bo- 
tanical Description of the j)onza 
muscipula,...in a letter to Sir 
Charles Linnezus,” p. 37) :— 
“The plant, of which I now enclose 
you an exact figure. . . . shows that 
Nature may have some views towards 
its nourishment, in forming the upper 
joint of its leaf like a machine to 
catch food.” 
Linneus was unable to believe that 
the plant could profit by the captured 
insects ; he only saw in the phenomena 
‘an extreme case of sensitiveness in 
the leaves which causes them to fold 
up where irritated, just as the sensi- 
tive plant does; and he consequently 
regarded the capture of the disturb- 
ing insect as something merely 
accidental and of no importance to 
the piant. . . . Linneus’s authority 
overbore criticism if any was offered ; 
and his statement about the behaviour 
of the leaves was copied from book to 
book... . Dr. [Erasmus] Darwin 
(1791) was contented to suppose that 
Dionza surrounded itself with insect- 
traps to prevent depredations upon 
its flowers. Dr. Curtis, whose con- 
tribution to the subject has been 
already mentioned, describes the 
captured insects as enveloped in a 
fluid of a mucilaginous consistence 
which seems to act as a solvent, the 
insects being more or less consumed 
by it.’—F. D.] 
+ [See footnote, p. 106.—F. D.] 
R 2 
