1914] 
DUGGAR AND MERRILL—ACIDITY OF TOMATO FRUITS 239 
were picked green and ripened in the incubator at 32-33°С. 
(10-22 days) exhibit a higher acid content than either those 
ripened on the vines or those ripened at the temperature of the 
laboratory. (3) There are considerable differences in the acid- 
ity of varieties, but judging from the results of these tests 
the normally ripened fruits of yellow varieties commonly con- 
tain as much acid as those of red varieties. 
The several facts brought out by these tests render it obvious 
that there is now no sufficient evidence to justify relating 
pigmentation to total acidity. Тһе acidity changes are, how- 
ever, interesting in themselves, in these as well as in other 
fruits. No attempt was made to follow progressively any 
changes in acidity induced by conditions; but in titrating on 
one occasion, after an interval of two days, new samples of 
both red and yellow fruits which had been ripened in the labo- 
ratory, it was found that the acidity had noticeably declined 
since the previous titrations from the same lots of fruits. 
We have reckoned the acidity of the tomato in terms of 
сігіс acid, as is customary. It should be noted, however, 
that while Bowman (3) and others report citric as the chief 
acid of the tomato, Albahary (1), on the contrary, gives .48 
per cent as the malic acid content and .09 per cent as that of 
citric acid in the fresh fruits. The author last mentioned 
gives no indications respecting the variety or condition of the 
fruit employed. In a later contribution (2) he reports the 
results of analyzing tomato fruits in different stages of matura- 
tion, as follows: “1916 fruit vert avant l'apparition de la graine 
dans la pulpe; 2? le fruit vert au moment oü la graine est 
complètement formée; 3? le fruit rouge arrivé à sa pleine matu- 
ration." Іп the second stage, corresponding to practically 
full grown, green, he finds .58, and in the ripe fruits .42 per 
cent of organic acids. This is in complete agreement with 
our findings. In the earliest stage of fruit development Alba- 
hary finds an acid content of only .116 per cent. Wehmer 
(5), after quoting Albahary (1) as to the percentage of the 
various acids in the fruit, remarks, “Піс Aciditüt wechselt 
stark je nach dem Reifestadium (von 0,06-0,697% des Saftes 
auf Citronensáure berechnet)." He does not indieate the 
