182 Distribution of Inorganic Matter in Vegetables. [April, 



plant, or without producing a visible deterioation — yet it is shown 

 that in the case of tobacco, the substitution of lime for potash, 

 injures greatly its commercial value. 



It is unnecessary to dwell here upon the importance of this 

 single discovery; for no one can fail to inquire, if the properties 

 of one plant are injured by substitutes, may not many of our most 

 important vegetables products be injured also; or may they not 

 be greatly improved by supplying them with certain inorganic 

 elements. An inquiry of this kind comes up at once, with re- 

 spect to our most important esculents and cereals; and probably 

 it will be found, that upon a supply of certain kinds of food, their 

 most important properties depend. 



7. I have already observed, though the remark may appear 

 hazardous, that former analyses of the ash give us only imperfect 

 views of the composition of the inorganic matters of an indi- 

 vidual species. The observation is founded upon a fact, which 

 appears to hold good in a majority of cases — namely, that the 

 wood of different parts of the same organ contain not only an 

 unequal quantity of ash, but an unequal distribution of the same 

 elements. For example, the wood of the trunk of most forest 

 and fruit trees contain a less percentage of ash in the inside than 

 the outside wood; and especially does this fact hold good, if the 

 bark is taken into consideration, which contains in some instances 

 ten times as much ash as the wood of any part of an individual 

 tree. 



When I had ascertained the necessity of analysing the bark 

 separately, not only on account of its composition, but also on 

 account of its great amount of ash, it occurred to me that possibly 

 a law may exist which controls the distribution of the ash in the 

 plant. This law I supposed might be represented by two com- 

 bined movements of the inorganic matter: one an outward move- 

 ment from the centre to the outside, and another by an upward or 

 an axial movement, by the same process, operating in that di- 

 rection. 



8. It may not be possible, however, to prove the first move- 

 ment, inasmuch as the diminution of inorganic matter may be 

 occasioned by its transference to the superior branches, in order to 

 contribute to their growth, rather than to the growth of the last 

 annual layers of wood, which constitute the outside of the tree. 

 The fact, however, which it is designed to convey is, that in pro- 

 cess of time, the inside or heart wood, loses a part of its inor- 

 ganic matter; that it contains less than when the heart wood was 

 itself the sap or outside wood. 



I do not, at this stage of inquiry, assert that the ash of the in- 

 side wood is always less than the outside. It is in a great ma- 

 jority of instances. Still, a few woods have been met with, in 



