Rev. P. Keith on Phytological Errors, with Admonitions. 209 



" On the fifth the radicle was |th of an inch in length, and the 

 marks nearly as before with regard to their relative distances, 

 but removed evidently from the integuments, so as to admit 

 a fourth or additional mark adjoining the integuments. The 

 radicle, which was originally upright, was now bending down. 



" On the sixth the radicle was •§■ an inch in length, the first 

 mark being within two or three lines of the point; the second 

 at about Jth of an inch from the first ; the third at about £th 

 of an inch from the second; and the fourth at about Jth of 

 an inch from the third, as well as perceptibly removed from 

 the integuments. 



"On the seventh the radicle was fths of an inch in length. 

 The first mark was still within two or three lines of the point ; 

 the second was at the distance of Jth of an inch from the first; 

 the third was at the distance of 5th of an inch from the second ; 

 and the fourth was at about £th of an inch from the third, 

 being but little more than its original distance, but removed 

 to the distance of £th of an inch from the integuments. 



" On the eighth the radicle was one inch in length, the first 

 mark being still near the apex; the second at the distance of 

 about Jrd of an inch from the first; the third at the distance 

 of ^rd of an inch from the second ; and the fourth nearly as 

 before. 



"On the ninth the radicle was \\ inch in length, the three 

 marks next the base being nearly as before, and the mark next 

 the apex being the only one that was carried down. 



" On the tenth, and as long as any further observations were 

 made, it was still the lower extremity of the radicle that was 

 carried down. But enough had been previously observed to 

 show that the assumed peculiarity of the elongation of the ra- 

 dicle is founded in a mistake; and that the root in its incipient 

 state, like the stem in its incipient state, is augmented by the 

 introsusception and deposition of additional particles through- 

 out its whole mass, or 'by a general extension of parts al- 

 ready formed,' though it may afterwards, like the stem, be- 

 come so firm and compact as no longer to admit of augmen- 

 tation in that way*." 



As connected with the presumed mode of the root's aug- 

 mentation, M. De Candolle takes occasion to speak of the 

 spongioles in which the small fibrils of the root terminate. 

 He represents them as being composed essentially of a cellu- 

 lar tissue. " Les spongioles des racines sont essentiellement 

 composees de tissu cellulairef." Yet this account of their in- 

 ternal structure does not seem to me to accord well with the 



* Annals of Phil., No. 76. t Phi/s. Veget., torn. i. pp. 71, 41* 



Third Series, Vol. 5. No. 27. Sept. 1834. 2 E 



