TANNIC ACID FOR STRAWBERRIES. 



fure" of Prof. M.'s idea, unless the statement of his — put forth at the same meeting of 

 the American Institute Farmers' Club, — that " toads eat strawberries," is to be taken as 

 an illustration. Perhaps it is held that tannic acid is a specific food for toads, and that 

 the toughness of their skins is owing to the tanning they have undergone from the effects 

 of that acid, contained in the strawberries the animals had eaten! 



But does any one suppose that tannic acid exists in the strawberry? If it did, it would 

 be an anomaly, as the malic, tartaric, and citric, are the distinguisliing acids of fruits; 

 and though I cannot refer to any chemical examination of the strawberry, it is reasonable 

 to suppose that its acid is one of these. Tannic acid may, to be sure, exist in the stem 

 and root, and so it does in many other plants, to which it has never been thought of ap- 

 plying it as food. Plants have probably the power of elaborating their own acids. 



Again, is it even known that old tan-bark contains any appreciable amount of tannic 

 acid? It is well known that tanners use it as long as any tanning " liquor" can be made 

 from it, and it is only thrown aside as " spent tan," when the tanning principle has 

 been thoroughly extracted. The acid which then remains is probiably the gallic. The 

 beneficial effects of the bark as a mulch, are probably chiefly mechanical — preserving the 

 moisture and friabilit}' of the soil. When mixed with the soil, however, it decomposes 

 slowly, and may thus form a source of carbonic acid, on which it is known plants feed. 

 But its value as manure is little or nothing till its natural acid is gone. 



Can a single instance be cited of the beneficial application of tannic acid to plants? As a 

 general thing, we know there is nothing more unwholesome for them than astringent acids. 

 For example, peat or muck, from hemlock swamps, (and sometimes from other localities,) 

 frequently contains a considerable amount of tannic acid, and when first dug, it is not 

 onl}' valueless as food for plants, but positively injitrioibs — turning the leaves yellow, and 

 checking the growth. The substance does not operate as manure, till rain, frost, and air 

 have dissipated the acid. 



It is true that strawberries have been known to grow well in reclaimed bogs; so have 

 Indian corn, potatoes, beans, &c.; but is there any more evidence that tannic acid con- 

 tributed to the growth of the former than the latter? Neither will grow well, till the 

 surf\ice of the soil has become changed and sxoietemd by decomposing agents. Cranber 

 ries, however, grow natural]}', on bogs, without any preparation of the soil: but it has 

 ever been pretended that tannic acid was a specific food for this plant, and its sour prin- 

 ciple is known to be citric acid. H. 



A.bany, Aug. 1, 1S51. 



Remarks. — It is we believe understood from recent chemical analysis that tannic acid 

 forms a part of the strawberry plant, (not the fruit,) and it is upon this ground that it is 

 considered especially beneficial to strawberry beds. From our own experience we cannot 

 positively speak of beneficial effects from tan, considered as a specific manure. But as a 

 malchzr we consider it by fiir the beet we have ever tried for strawberry beds. 



Prof. Mapks, however, in a conversation that we had with him a short time ago, as- 

 sured us that he had watered his beds with diluted tannic acid with good results, and we 

 hope he will give liis own more complete experience for the benefit of our correspondent. 



Tan-bark, fresh from the pit, does Ave tliink contain a considerable amount of tannic 

 acid — as we have known it to injure very delicate plants, though robust ones do not mind 

 it at all. Ed. 



