82 Mr. Knight on the Radicle and Germen of Seeds. 



itself be planted, its germ -will be seen to incline towards any 

 point from which it receives most light; whilst the germ spring- 

 ing from the seed of ivy, or other plant which nature intended 

 to rely upon the support of some other body, will recede from 

 light and seek the shade ; but the radicles of all will be found 

 to proceed alike perpendicularly downwards; and, therefore, 

 if the specific gravity of the radicles had exceeded that of the 

 germs to the extent conceived by M. Poiteau, that circum- 

 stance, as the seeds in my experiments were bound firmly to 

 the circumference of the wheels, could not, in any degree 

 whatever, have caused the germs in their growth to have 

 approached their axis of rotation. M. Poiteau must, there- 

 fore, allow me to consider his production as a succession of 

 blunders from beginning to end. 



I wished M. Dutrochet to refute M. Poiteau's hypothesis; 

 but he seemed to think that M. Poiteau's errors would be 

 obvious to every reader before he could publish his exposition 

 of them; and I should have agreed in opinion with M. Du- 

 trochet if M. Poiteau's communication, instead of his assump- 

 tion, had been published in the 'Quarterly Journal of Science;' 

 but, as it was not, and as the knowledge of the influence of 

 gravitation upon the moving fluids of plants, and conse- 

 quently upon their growth, forms, and produce, is important to 

 the scientific gardener ; and as I had the honour to receive 

 from the Royal Society Sir Godfrey Copley's medal for the 

 memoir which gave a statement of my facts and hypothesis, I 

 have thought it proper to shew that M. Poiteau's conclusions 

 are not quite so accurate and unquestionable as he appears to 

 have imagined them to be. 



Downton, July 8, 1831. 



