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M. Vauquclin could not obtain a sufficient quan- 

 tity of the sap of the horse-chesnut for examination; a 

 circumstance much to be regretted; and he has not 

 stated the relative quantities of the different substances 

 in the buds, leaves, flowers, and seeds. It is proba- 

 ble, however, from his unfinished details, that the 

 quantity of resinous matter is increased in the leaf, and 

 that the white fibrous pulp of the chesnut is formed 

 by the mutual action of albuminous and astringent, 

 matter, which probably are supplied by different cells 

 or vessels. I have already mentioned* that the cam- 

 bium, from which the new parts of the trunk and the 

 branches appear to be formed, probably owes its pow- 

 er of consolidation to the mixture of two different 

 kinds of sap; one of which flows upwards from the 

 roots; and other of which probably descends from the 

 leaves. I attempted, in May 1 804, at the time the 

 cambium was forming in the oak, to ascertain the na- 

 ture of the action of the sap of the alburnum upon the 

 juices of the bark. By perforating the alburnum in a 

 young oak, and applying an exhausting syringe to the 

 aperture, I easily drew out a small quantity of sap. 

 I could not, however, in the same way obtain sap from 

 the bark. I was obliged to recur to the solution of 

 its principles in water, by infusing a small quantity of 

 fresh bark in warm water; the liquid obtained in this 

 way was highly coloured and astringent; and produc- 

 ed an immediate precipitate in the alburnous sap, the 



* Page 131.. 



