250 PROCESS OF DEVELOPEMENT. CHAP. IV. 



to the lac- analogous to the lacteals of the animal system, 

 imals. which absorb the food digested by the stomach. 

 But at this rate we must also regard the earth as 

 being the stomach of plants, which analogy, as I 

 think, will not hold good. For the root is rather to 

 be regarded as the mouth of the plant, selecting 

 what is useful to nourishment and rejecting what is 

 yet in a crude and indigestible state ; the larger por- 

 tions of it serving also to fix the plant in the soil and 

 to convey to the trunk the nourishment absorbed 

 by the smaller fibres, which ascending by the tubes 

 of the alburnum, is thus conveyed to the leaves, 

 the digestive organs of plants. 

 Said to die Du Hamel thinks that the roots of plants are 



11 



likc U th e y furnished with preorganized germes by which they 

 are ena bied to send out lateral branches when cut, 

 though the existence of such germes is not proved ; 

 and affirms that the extremities of the fibres of the 

 root die annually like the leaves of the trunk and 

 branches, and are again annually renewed ; which 

 last peculiarity Professor Wildenow affirms also to 

 be the fact,* but without adducing any evidence by 

 which it appears to be satisfactorily substantiated. 

 On the contrary Mr. Knight, who has also made 

 some observations on this subject, says, it does not 

 appear that the terminating fibres of the roots of 

 woody plants die annually, though those of bulbous 

 roots are found to do so.-}- 



* Princ. of Bot. Eng. Trans. 262. i Phil. Trans. 1809. 

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