106 “Be REPORT—1874. 
on the leaf-stalk.” Upon opening these leaves, he says :—“TI found in each a dead 
insect; hence I imagined that this plant, which has some resemblance to the 
Dionea muscipula, might also have a similar moving power.” 
“ With a pair of pliers I placed an ant upon the middle of the leaf of D, rotundi- 
folia, but not so as to disturb the plant. The ant endeavoured to escape, but was 
held fast by the clammy juice at the points of the hairs, which was drawn out by 
its feet into fine threads. In some minutes the short hairs on the disk of the leaf 
began to bend, then the long hairs, and laid themselves upon the insect. After a 
while the leaf began to bend, and in some hours the end of the leaf jwas so bent 
inwards as to touch the base. The ant died in fifteen minutes, which was before 
all the hairs had bent themselves” *, : 
These facts, established nearly a century ago by the testimony of independent 
observers, have up to the present time been almost ignored ; and Trécul f, writing 
in 1855, even thought that the facts were not true. 
More recently, however, they have been repeatedly verified :—in Germany by 
Nitschke, in 1860}; in America by a lady, Mrs. Treat, of New Jersey, in 1871§; 
in this country by Mr. Darwin, and also by Mr. A. W. Bennett ll. 
To Mr. Darwin, who for some years past has had the subject under investigation, 
we are indebted, not merely for the complete confirmation of the facts attested by 
the earliest observers, but also for some additions to those facts, which are 
extremely important. The whole investigation still awaits publication at his hands ; 
but some of the points which were established have been announced by Professor 
Asa Gray in America, to whom Mr. Darwin had communicated them§. He found 
that the hairs on the leaf of Drosera responded to a piece of muscle or other animal 
substance, while to any particle of inorganic matter they acted less efficiently, and 
the periods of subsequent reexpansion were widely different. To minute fragments 
of carbonate of ammonia they were more responsive. 
The results of Mrs. Treat’s experiments I will give in her own words :— 
“ Fifteen minutes past ten I placed bits of raw beef on some of the most vigorous 
leaves of Drosera longifolia. Ten minutes past twelve two of the leaves had folded 
around the beef, hiding it from sight. Half-past eleven on the same day, I placed 
living flies on the leaves of D. longifolia. At twelve o’clock and forty-eight 
minutes one of the leaves had folded entirely around its victim, and the other 
leaves had partially folded, and the flies had ceased to struggle. By half-past two 
four leaves had each folded around a fly. The leaf folds from the apex to the 
petiole, after the manner of its vernation. I tried mineral substances, bits of dry 
chalk, magnesia, and pebbles. In twenty-four hours neither the leayes nor the 
bristles had made any move in clasping these articles. I wet a piece of chalk in 
water, and in less than an hour the bristles were curving about it, but soon unfolded 
again, leaving the chalk free on the blade of the leaf.” 
Time will not allow me to enter into further details with respect to Dionea and 
Drosera. The repeated testimony of various observers spread over a century, 
though at no time warmly received, must, I think, go a long way towards satisfying 
you that in this small family of the Droseracee we have plants which, in the first 
place, capture animals for purposes of food ; and, in the second, digest and dissolve 
them by means of a fluid which is poured out for the purpose ; and, thirdly, absorb 
the solution of animal matter which is so produced. 
Before the investigations of Mr, Darwin had led other persons to work at the 
subject, the meaning of these phenomena was very little appreciated. Only a few 
years ago, Duchartre, a French physiological botanist, after mentioning the views 
of Ellis and Curtis with respect to Dionea, expressed his opinion that the idea 
that its leaves absorbed dissolved animal substances was too evidently in disagree- 
ment with our knowledge of the function of leaves, and of the whole course of 
vegetable nutrition, to deserve being seriously discussed]. 
* Quoted by Withering, Z. c. i 
t “Je pense que ces organes ne sont pas excitables; je crois qu’ils ne sont pas suscep- 
tibles d’exécuter les mouyements qu’on leur attribue.’—Ann. des Sc. Nat. 4° sér. t. iti. 
p. 303. 
{ Bot. Zeit. 1860, p. 229. § American Naturalist, 1873, p. 705. 
|| Brit. Assoc, Rep, 1878, Trans. Sect. p. 128. Eléments de Botanique, p. 308. 
