may be detected. I know no reason why the converse of this statement is not true 

 why one two-hundred thousandth part of tannic acid niaj' not be detected by the salt of 

 iron. If with this exceeding! j^ delicate means of discovering tannic acid, Prof. Mapes, could 

 only find it by using a large quantity of the cortical surface of the strawberry, it may be 

 questioned whether the tannic acid has a very large influence on the flavor of that fruit! 

 Tannic acid is however readil}"^ detected in the leaves and stems of the strawberry, as I have 

 this day observed, by the use of the above mentioned test. Still the quantity is small, as 

 nothing of the intensely bitter taste of tannic acid can be perceived. In order to test this 

 predicate, (Prof. Mapes' presentation of tannic acid as a constituent of the strawberry,) 

 and the comparative powers of the citric and malic acids, as " nutrition for the strawberry," 

 Dr. Hull made a series of experiments, on " three rows of each variety, of four different 

 kinds of strawberries, which traverse his triple bed of inorganic manures. The liquids 

 were applied from May 18th to June 23d, twenty-five times. The liquids were: — 



Tannic acid — in the fom of tan-brark liquor, one gallon to one Imndred of water j 



Citric acid — juice of one lemon to four gallons of water; 



Malic acid — one pint of cider to four gallons of water; 



Manure water — manure licjuid of the barn-yard; 



Poudrette water." 



I must refer the reader to the August Horticulturist, for the details of these experi- 

 ments. The general result was that the tan-liquor produced the best yield always, as 

 regards quantity, and generally M'ith respect to quality. 



This result has its practical value, which cannot be denied; but has it received the cor- 

 rect explanation } Without assuming to give the correct explanation on so insufficient 

 data, I beg to indicate some reasons, that in my mind show that it is j'et unproved, that 

 tannic acid has produced these effects. I do not deny that it may be the principal agent; 

 but I conceive that Prof. Mapes' assertion, though having a degree of plausibility, re- 

 mains to be demonstrated. 



What is Dr. Hull's tannic acidl Is it the very nearly pure substance? It is tan- 

 liquor — whether fresh or spent, furnished by oak, hemlock, sumach or catechu, he does 

 not tell us ! 



May there not be many other substances present in it besides tannic acid ? We know 

 that the bark of trees is rich in inorganic bodies. Can they be excluded from participa- 

 ting in the effect } The ready passage of tannic acid into gallic acid is well known. Is it 

 not worthy of consideration ? It has recently been discovered in the Giessen laboratory, 

 that tannic acid is a compound of gallic acid and sugar, and since it readily decomposes into 

 these two bodies, they may Avith as much propriety be concerned in the nutrition of the 

 plant. However, we know nothing about it. 



In two cases, the strawberries in Dr. Hull's experiments, that he fed with malic acid, 

 were adjudged to possess the highest flavor. What is Dr. Hull's malic acid? Cider! 

 containing, according to Dr. Salisbury's analysis, alcohol, sugar, dextrine, malic acid, 

 phosphates and sulphates of the alkalies, with a little tannic and gallic acids. 



Says Dr. Hull — "Here arises an important inquiry — how much of the flavor 

 allowed to the malic acid, must be attributed to the tannic acid which the cider contained.'" 

 It may not, perhaps, be irrelevant to inquire what part of the flavor of cider, or of cider 

 apples, may be due to tannic acid .' 



What eff"ectniay the alcohol, sugar, and alkaline, phosphates, and sulphates have had on 

 the strawberry flavor ? 



Hull does not specify the age of his cider, a matter of much importance; fo 

 known that malic acids and its salts easily enter into decomposition. 



