484 Theory of the Nutrition [BOOK nf. 



red inside. It was a natural conclusion at that time, that 

 it was these parts which chiefly absorbed the red colouring 

 matter, and in fact this opinion was maintained till quite 

 recent times, and it was on such results that Pyrame de 

 Candolle founded his theory of the spongioles of the root, 

 which is still accepted in France. At present it is known, 

 that the bark and especially the youngest tips of the fibres 

 of the root are not coloured under these circumstances, until 

 they have been first poisoned and killed by the colouring 

 matter ; these experiments therefore, which have been fre- 

 quently repeated since De la Baisse's time, prove nothing 

 respecting the action of living roots, but they were from the 

 first the cause of a pernicious error in vegetable physiology, 

 which as we shall see gave rise to others also. One result 

 however of De la Baisse's experiments was less misleading ; 

 he placed the cut ends of branches of woody plants in the 

 coloured fluid, and found that not only the general body of 

 the wood, but the woody bundles which pass from it into the 

 leaves and parts of the flowers, were coloured red, while the 

 succulent tissue of the bark and leaves remained uncoloured. 

 It appeared therefore that the red juice passed only through 

 the wood, and a somewhat bold analogy might lead to the 

 further conclusion that this is true also of the nutrient sub- 

 stances dissolved in the watery sap ; but the view so stated 

 is not at present considered to be correct, and that the sap 

 which ascends from the roots to the leaves, the water especially, 

 is conveyed through the wood only, and not through the rind, 

 had been already sufficiently proved by the experiments of Hales 

 and others. The uncritical treatment of experiments of this kind 

 by GEORG CHRISTIAN REiCHEL 1 afterwards led to new errors, 

 though his dissertation, c De vasis plantarum spiralibus,' shows 

 to advantage by the side of similar productions of the day 



1 Georg Christian Reichel was born in 1727 and died in 1771. He was 

 Professor in the University of Leipsic. 



