Volume 1
Descriptive and illustrated catalogue of the physiological series of comparative anatomy contained in the museum of the Royal College of Surgeons in London.
- Royal College of Surgeons of England. Museum
- Date:
- 1833-1840
Licence: Public Domain Mark
Credit: Descriptive and illustrated catalogue of the physiological series of comparative anatomy contained in the museum of the Royal College of Surgeons in London. Source: Wellcome Collection.
Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.
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![the point to which each leaf fell, the time it took to rise, and the point to which it rose, were carefully registered.] From these experiments we may draw the following conclusions :— That there is no fixed time for any of the leaves of the plants to move through its course. That they are less affected as they become accustomed to the stimu- lus ; but the power of collapsing is increased (although not in the same degree), so that they do not move through the same arc. That they require a stronger or quicker stimulus to produce motion after being some time accustomed to it; which was evidently seen in comparing these with others which had not been stimulated. It may also be observed, that when these plants collapse in the evening, they have nearly the same quantity of flexion as when roughly touched at noon : but if touched after they have collapsed from the effect of the evening, they become much more bent than by the same [degree of] touch at noon. This would seem to arise from a disposition to collapse in the evening, and a power of increasing that disposition and action when stimulated. Their collapsing more in the day, and erecting themselves less after a repetition of such actions, may assist in explaining the principle on which this depends. John Hunter, MS. Croonian Lectures, No. 1. Subsequent experiments on this subject have been made by Mr. Lind- say (Paper read before the Royal Society, A.D. 1790.), by Dr. Dutrochet {Journ. de Phys. xcv. p. 474.), and by Professors Mayo and Burnett {Outlines of Physiology, p. 11. 2nd ed. and Quarterly Journal of Science, XXV. p. 434.), which prove, that the tuber at the articulation of each leaf with the stalk is formed by antagonist elastic springs, the superior serving to depress, the inferior to elevate the leaf; for, if the upper part of the intumescence be cut through, the leaf rises more than natural, and no irritation however violent can cause it to collapse; that if the under part be divided, the leaf falls, and by no extent of rest will it again be enabled to rise ; also the lateral parts being cut, a lateral flexion is caused towards the wounded side. Similarly acting organs exist at the articu- lations of the pinnules, and of the leaflets ; only in the one case they are](https://iiif.wellcomecollection.org/image/b21470315_0001_0027.jp2/full/800%2C/0/default.jpg)
