in the Roots of Dicotyledonous Plants. 113 



panulate. Were I to theorize upon the possible functions of 

 these, the first instruments of the vital principle, I should pro- 

 bably be met by the rebuke, justly merited indeed when but 

 few facts form the basis of confident speculation, " La theorie ! 

 la theorie ! peut-etre que de long-temps encore il nous sera pas 

 permi de nous guider dans ces recherches a la lueur d^un autre 

 flambeau." I pass on, therefore, to describe the structure of 

 the root. 



The medullary canal of the stem with its system of vessels 

 is continued without any interruption into the body of the 

 root ; or perhaps it would be more accurate to invert the order 

 of these terms, as the root is first developed. The cellular 

 tissue of the young root is studded throughout its entire length 

 with fine fibrils. These I notice for the sake of observing 

 that their length varies under different circumstances of 

 growth. If the seed be well supplied with water these fibrillae 

 are short, but if the seed be allowed to attach itself to the side 

 of a bottle, for instance, and a few inches from the surface of 

 the water, their length is considerable, and they are constantly 

 beaded, as it were, with small condensed drops of the ascend- 

 ing vapour. It is evident that, in the latter case, the demand 

 for nutriment being greater than the supply, Ave have a clue 

 to the beautiful contrivance of the elongation of the absorbent 

 vessel. I will here add, though I cannot at present go into 

 the important questions connected with the statement, that 

 the plants which I am now describing were raised in distilled 

 water, and fed by the vapour of distilled water. 



In addition to these interesting facts connected with the 

 germination of mustard seed, it only remains for me to state 

 that the column of vessels which is found in the body of the 

 root is composed of dotted ducts, derived from the apposition 

 of short cylindrical cells, base to base, annular vessels and 

 spiral vessels. The latter are without doubt "the true vessels 

 which strictly compose the vascular tissue." 



Hoping that these few remarks will serve to elucidate this 

 subject, I am, my dear Sir, 



Faithfully yours, 



J. B. Reade. 



Ann. Nat, Hist. Vol. 1. No. 2. April 1838. i 



