202 Distribution of Inorganic Matter in Vegetables. [April, 



It is not a little remarkable that plants which possess apparently 

 so small a share of vitality, should be able to take from a rock its 

 potash, lime, and phosphates. It will be observed, however, that 

 they adhere with as much tenacity to the rock as a shrub to the 

 earth, and that it is as easy to extract the one as the other from 

 its bed. It would seem, from this single examination, that the 

 presence of the element of rocks may be determined by an exam- 

 ination of the ash of the plant which grows upon it. 



The results of the foregoing analyses may be studied in some 

 of the most important facts which they contain. 



The first fact which it seems proper to notice here, is the per 

 centage of inorganic matter which is contained in the parts of the 

 wood and bark. On this point I would speak with caution, par- 

 ticularly with regard to the diiference of ash contained in equal 

 quantities of sap and heart wood. It is, however, as it seems to 

 me, too common an occurrence, to find the ash greater in the sap 

 wood than in the heart wood, to be due to accident. But inas- 

 much as instances do occur, in which it is directly the reverse, it 

 becomes necessary to wait the results of an additional number of 

 analyses, before I should venture to say that the law referred to 

 prevails. In the case of the iron-wood, this excess is due to the 

 potash in the heart w'ood; and it will be seen that the oxygen of 

 the bases is greatest in the outside wood. 



Leaving for the present this question, I may state with entire 

 confidence, that the bark of all kinds of trees is more largely sup- 

 plied with inorganic matter than any other part of the tree. This 

 position is sustained at least by all the foregoing analyses. The 

 fact is this, to state it more particularly, that the old bark of the 

 trunk is richer in inorganic matter than the newer bark of the 

 branches. The element which predominates in the bark is lime. 

 This substance is probably better adapted to protect the outside 

 of the tree from injury than any other. It is a more perfect de- 

 fence to the tender and growing wood immediately beneath. As 

 in the animal tissues, outward defences are set up, so the vegeta- 

 ble is not left unguarded in any of the tissues which are liable to 

 outward injuries. 



But this is not all: a practical rule of great importance flows 

 from the fact that lime predominates in the bark and other parts 

 of plants. It is to supply lime freely to the tree. This rule may 

 not be regarded as new; and yet its importance is placed in a 

 clear light by the foregoing analyses. The farmer may no longer 

 fear that he shall poison his trees by its use, since, under all cir- 

 cumstances, it is found so abundantly in its tissues, forming, as we 

 have already stated, a substitute for an osseous or frame-work for 

 the support of the organic matter. This frame-work is more 



