S70 



Tnstance of its 

 iaiiger. 



DIRECTION OF THE GROWTH OF ROOTS. 



from the ignorance of herbalists, or of those who use this 

 plant, respecting its virtues. 



To mention only one recent instance: a man complain- 

 ing of a pain in the loins, where one of those good women 

 were present, who act gratuitously as physicians, and have 

 a remedy for every disease ; she advised him to have recourse 

 to clysters of a decoction of hedge hyssop. Unfortu- 

 nately he too readily followed the prescription ; for, a few 

 moments after the remedy was administered, he was seized 

 with violent griping pains, and these were succeeded by 

 evacuations of blood, which continued for more than a 

 week; and, but for the assistance of a skilful physician, 

 who ought to have been consulted before, he would pro- 

 bably have lost his life. 



viir. 



On the Causes which hifluence the Birection of the Growth 

 of Roots. % T. A. KKifiHT, Esq. F.R.S. In a 

 Letter to the Right Hon, Sir Joseph Banks, Bart. 

 K.B. P.R.S*. 



1 HAVE shown, in a former communication, the effects 

 of centrifugal force upon germinating seeds; from which I 

 have inferred, that the radicles are made to descend towards 

 the earth, and the germes, or elongated plumules, to take 

 the opposite direction, by the infltience of gravitation ; and 

 I believe the facts I have stated to be sufficient to support 

 the inferences I have drawn +. But the fibrous roots of 

 plants, being much less succulent, though not uninfluenced 

 in the directions they take by gravitation, are, to a great 

 extent, obedient to other laws, and are generally found to 

 extend themselves most rapidly, and to the greatest length, 

 whence suppos- 11 whatever direction the soil is most favourable: whence 

 ed to have per- many naturalists have been disposed to believe, that these 

 are guided by some degrees of feeling and perception, 

 analogous to those of animal life. 



iTrowth of 

 radicles. 



Fibrous roots 

 obedient to 



*ther laws } 



ception. 



* Phil. Trans, for 1811, p. 209. 



t Fliil. Trans. 1800, page 5 : or Journal, vol. xiv,p. 409. 



I shall 



