CH. IT. 



MISCELLANEOUS. 



Ill 



tlie heart-wood so ''filled with secretions ' that there is 

 no room even for the upward sap to ascend through it. 

 Yet now he makes it convey both upAvard and down- 

 ward sap, for there can be no sap-wood under an old 

 scar.. But this voluminous compiler of other people's 

 ideas, states all, however incompatible or contradic- 

 tory one may be to the other, and uses either as con- 

 venient Here he makes the growth in diameter to be 

 the result of ' the falling sap.' A httle before he 

 adopts, confidently, the theory of Darwin and Du 

 Petit'-Thouars. In this there is no ' falling sap ' allowed ; 

 but a downward growth ' of organic fibres descending 

 from the leaf-buds.' If this theory were true, a com- 

 mon mind would shrink from the difficulty of passing 

 these organic fibres through the medullary plates, even 

 the first year : but it would require a Lindley to face 

 the annually increasing difficulty ; especially as neither 

 the barked part of the stem, nor the part below it, is 

 to increase in girthing by these excessive growths and 

 deposits of organic fibres. Or, if the barked part is to 

 increase it must be on the principle of one of De 

 CandoUe's monocotyledonous endogens ; I like sesqui- 

 pedalia ! 



Mr. Wallis brings forward a fact which is, perhaps, 

 as complete a stunner as the Doctor's theory. He gives 

 a portrait of a thorn which lived and grew for seven 

 years after its stem was sawed across and divided from 

 its roots : ' On examination, the lower part of its stem 

 had remained of the size it was when sawed through ; 



