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(Before giving the experiments on which these remarks are founded; I must briefly describe the structure of the leaf leaves. These are circular with a [illeg] long footstalk, & with the whole upper surface covered bearing hairs, each surmounted by a gla head or gland. I have counted 186 198 of these hairs on one moderately large leaf. Those on the disc are short & of equal length projecting perpendicularly; becoming towards the margins they become longer & of equal length than the long hairs on the margins project in to plane of the leaf disc of its leaf or were covering an a little reflexed.

When the leaf happens to stand vertical the extreme marginal hairs are often reflexed at right angles; & when these hairs become increased over a small object on the disc, they move through no less 270 degrees.   Used   The structure of the hairs has been described (see previous note) by M. M. Groenland & Trécul: the stem of the is formed of elongated cells containing a homogenous pink fluid; it is furnished with stomata & has a spherical vessel running up the middle. The heads or glands are formed of polygonal cells & containing either a [2 words illeg] fluid or an orbicular & broken mass of greenish & these cells surrounding a collection group of layers & oval, colourless cells [illeg] with a specially marked cells. The   (a)  whole head or gland is oval of all the hairs, excepting those on the extreme margins is oval & surmounts the extremity of the hairs & is distinctly separated from the hair-like footstak; but but in the extreme marginal hairs in which the gland is much elongated & projecting slightly,  not at the extremity, but along the upper face of the extremity terminal part of the Hair, Hence in external appearance   which forms a cushion beneath the gland

[See Insectivorous plants, pp. 9-10.]

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(a)

The exterior polygonal cells contain either a homogenous pink fluid, or an orbicular & broken collection of purple granules; but this latter substance I believe arises solely from the gland cells having lately acted as absorbant been in strong action as absorbants or secretions. The

[See Insectivorous plants, p. 6]

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Hence these extreme martinal hairs present there is a considerable difference in external appearance but none in essential structure or in function. The long-headed hairs generally act after the others, but this may be owing to their external marginal position. As a proof of this identity of stature I may state that I several times observed every intermediate grade of station between these two forms of the glands, in plants which opened their leaves when kept in water on plates. From the presence of the spiral vessel in the hairs, & from their mode of development. M. Grönland argues that these organs are not properly hairs, but prolongations of the leaf; but for convenience sake I shall still call them hairs.    Tenticles

[See Insectivorous plants, p. 4]

The Each gland on the summits of the hairs secrets a large drop of fluid, which glistening in the sun has given to the plant its poetical name of Sun-dew. As we shall hereafter see the glands are likewise absorbant capselle of [illeg] rapid absorption of fluid & gases. These frops of fluid seculed in extremely viscid & can even be drawn out into threads.   Acid   Immediately that a fly alights on a leaf it is intricately entangeld.

The fluid appears colourless, but when after a little ball of paper has been closed over, it is found stained pink showing that the fluid is slightly pink coloured like the contents of the cells.— The fluid

Grönland, Johannes. 1855. Note sur les organes glanduleux du genre Drosera. Annales des sciences naturelles (botanique) 4th ser. 3: 297-303. Darwin's abstract is in CUL-DAR60.1.51-53.

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is weekly acid & colours litmus-paper. Whilst the hair are slowly curving in over any object organic or inorganic, it always seemed to me (& I came to this conclusion before I saw the bearing of the fact on the movement of the hairs) that the glands secreted are extra amount of fluid. What is certain is that when as long as a fly is caught remains clasped by the hairs it is bathed by the secreted fluid. This occurs in d according to Mr Curtis, with flies caught by the Dionæa in N. America; & this author thought that the fluid acted on disintegrated & almost dissolved the insects: caught I came to the same conclusion, but on learning the same kinds of flies on the leaves & on damp moss under the same temperature for equal times I could perceive no difference in their degrees of tenderness. On the contrary the fluid seems rather antiseptic;

[Detail]

at least with two equal sized bits atoms of raw meat one placed left during 48 hours in warm weather on a leaf & on the moss; the latter became in days far more decayed, swarmed with infusoria & I could no longer clearly distinguish the transverse striae on the on the muscular, which whereas the striae were still plain in the mean clasped bathed by the secreted fluid. This fact does not seem to be incompatible with the fluid glands absorbing nutritious matter, anymore than in the case of secreting gastric juice which as the stomach checking putrifaction.

Curtis, Moses A. 1834. Enumeration of plants growing spontaneously around Wilmington, North Carolina, with remarks on some new and obscure species. Boston Journal of Natural History 1: 82-140.

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After

(During the act of inflection the pink fluid in the cells of the hairs undergoes a process of aggregation & becomes broken up into sphere & cylinders, accompanied by some remarkable phenomena presently to be described.   (After remaining clasped for some days over a fly.)   the heads or gland become absolutely black from opacity & apparently shrink a little.   They thus close to secrete fluid & become dry & are generally surrounded by a film of slightly opake, fibrous white matter, which is the viscid fluid dryed. This temporary cessation of the act of secretion is seems seems to be connected in an important manner with the act of reexpansion. Shortly after the hairs have reexpanded, the glands begin to secrete again; & they are then ready to clasp again any object placed on the disc.

In old leaves, however, the gla glands after reexpanding to reexpansion drop off, & the whole organ becomes functionless. The temporary drying of the glands is useful of use to the plant in another way independently of the mechanism of movement; for after bits of moss or stick or seeds have been blown fallen  a leaf & have been clasped, as soon the hairs which were touched are reexpanded & become dry such objects can be blown off by a breath of air, as I have often tried; but had it not been for this they would have remained for ever entangled by

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The viscid secretion nevertheless [illeg] all the glands not temporarily drying at the same time, fragments of irregular bodies such as flies often remain entangled, & during the act of reexpansion insects become dismembered.

I will now give a few of the many experiments which I tried to [illeg] my preliminary remarks on the rate & manner, in which of the closing of the leaves. [pencil insertions largely illeg] I irritated a leaf with a stiff brush, in 70 minutes

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(When an object is placed on the centre of the leaf, the immediately surrounding hairs first bend inwards, then those nearer to margins & finally the long-headed marginal hairs; & as the hairs increase in length towards the margins, when inflected, their heads glands all nearly meet over the centre. [3 words illeg]    As the extreme marginal hairs become inflected, the solid edges of the leaf [2 words illeg] curve irregularly inwards with [illeg] so laterally & & the whole plan surface of the leaf bends inward, with respect to the footstalk of the leaf & forms an obtuse angle with it. When I here, however, observed that when a minute drop of milk or other such fluid has been placed on a leaf, its edge here sometimes curled occasionally curved in before the hairs were much inflected. Whether the lateral or terminal edges of the leaf become inflected is variable under conditions apparently exactly the same as same. When an object is placed on the centre of th a leaf the irritation & consequent movement slowly spreads centrifugally at the same rate to the whole circumference of the leaf; but where an object is placed on one side, the irritation spreads centrifugally on that side alone & then afterwards laterally. For instance

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(All Used)

(When a minute flu, or bit of raw meat or other…object    When insects flies or bits of raw meat    are placed on the viscid glands of a single marginal hairs (either long- or mid-headed) I have seen these hairs    from their length curve bend over the heads of the others.)   without touching any other gland  these several , through the space of 180 degrees flies fly, without touching any other gland    bring placed the from its length  place the fly object   in the space of 35 minutes in to exact middle of the disc; without being touched carry other glands or t in six hours subsequently the hairs all round the leaf had pretty well embraced these flies & in eleven hours they were well enclosed, & still more perfectly next morning.) An excessively minute fly & bits of [illeg] paper &c were moved more slowly to the centre. Sometimes two or three hairs immediately joining that on which the fly is placed moves by sympathy.) When a fly is pla caught by four or five marginal & submarginal hairs it cannot be carried by a single slow swing from the margin to the centre of the leaf, but is clearly rolled form gland hairs sticky gland to hair gland, & as the hairs of each become inflected in more the fly slowly reaches to nearly the centre of the leaf; & then all the circumferential hairs clasp over it. From these facts we see that irritation does not at first spread quickly from th a single hair or from the few marginal hairs which first catch the fly, but from the hairs of the central hair after the fly has been brought there; & this seems an special circumstance that the object caught should else be come into contact with the glands.  embraced by all the hairs.   Of also the hairs on ( the leaf.