8 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 
performed by Patterson (36), Bishop and Patterson (12), Voorhees 
(55), Alwood (3), Alwood and Bowman (4), Bailey and Lodeman (8), 
Bailey (7), and Jenkins and Britton (26). 
There has been no little difference of opinion concerning the kind 
of acid occurring in the tomato. As before stated, Bertagnini (37) 
isolated and identified the acid as citric, while McElhenie (30) be- 
lieved that oxalic, citric, and malic acids were present. Patterson 
(36) makes the following statement: 
On following the schemes for the detection of organic acids as given in Fresenius's 
Qualitative Analysis, paragraph 193, page 342, and Prescott's Organic Analysis, page 
336, the following acids were found to be present in the concentrated juice of the 
tomato, viz, malic, tartaric, benzoic, and formic. Malic acid predominated and the 
others appeared to be present in very small quantities, and as there has been no time 
for a further investigation as to the relative amounts of these, the whole of the free 
acids has been calculated as malic acid. 
Passerini (35) claims that the acidity is due chiefly to citric acid 
and makes the statement: l 
II sapore dolce e dovuto a glucosi, i quali hanno azione resultante levogira sulla 
luce polarizzata; l'acidita per la massima parte ad acido citrico, come dimostrammo 
in altra nota. 
Briosi and Gigli (13) also confirm the presence of citric acid: 2 
Queste esperienze provano nel liquido giallo la presenza dell'acido citrico; esiccome 
isaggi con l'acqua di calce e col cloruro di calcio, ed altri che per brevita non rife- 
riamo, escludono l'acido tartarico, possimao credere che l'acidita stessa sia, almeno 
per la massima parte dovuta a esso acido citrico, gia riconosciuto nel pomodoro per la 
prima volta da Bertagnini. 
Alwood and Bowman (4) make the following statement: 
A qualitative examination showed the presence of citric, malic, tartaric, formic, 
and succinic acids. Of these the citric acid was by far the most abundant, so that in 
the quantitative determinations the whole acid was calculated as citric acid. 
Stiiber (50) reports that apparently all the acid present was citric, 
and in no case was tartaric, malic, or succinic acid found. 
Formenti and Scipiotti (19) claim that salicylic acid occurs 
naturally in the tomato to the extent of 15 to 25 milligrams per kilo- 
gram of fresh fruit juice. 
Albahary (1) gives the following acids as occurring in the tomato: 
Malic, 0.48 per cent; citric, 0.09 per cent; oxalic, 0.001 per cent; 
tartaric and succinic, traces. He also reports the presence of an 
amino acid (2). 
Bacon and Dunbar (6) state that — 
the acid of tomatoes has been called by various authors malic, citric, tartaric, and 
oxalic. The acid is actually citric, as shown. * * * 
1 Translated as follows: The sweet taste is due to glucose , which has a resulting levorotatory action upon 
polarized light; the greatest part of the acidity is due to citric acid, as we have shown in a prcnous note. 
2 Translated as follows: These experiments prove the presence of citric acid in the yellow liquid: experi- 
ments with lime water and calcium chlorid and others which we do not mention for the sake of brevity 
exclude tartaric acid. We may hclieve that this same acidity is due, at least for the most part, to that 
citric acid already recognized in the tomato for the first time by Bertagnini. 
