204 
BRITISH PHARMACEUTICAL CONFERENCE. 
great for the acid. In Muspratt’s* Dictionary,’ juice containing seven per 
cent, or 31*5 grains per ounce, is termed very superior. In Mr. Watt’s 
splendid work, 4*7 per cent, or 20% grains per ounce is quoted as the amount. 
Muspratt says that lemons at an earlier part of the season are more acid, 
and as the season advances the water is a percentage or two higher. All 
these statements are so greatly at variance with the results I have found, 
that I am induced to bring the subject before the Conference. 
As will be seen, the Board of Trade have fixed very liberally for the 
vendors the specific gravity of T030 as the standard, and 30 grains per 
ounce as the least quantity of acid. 
On February 25th of this year I bought a lot of lemons from six dif¬ 
ferent shops, and after mixing them, I pressed eight, which gave seven 
ounces of juice, having a specific gravity of from T040 to 1*046, and yielding 
40 to 46 grains per ounce, or 9'6 per cent, of citric acid. 
The specific gravity was taken by one of Griffin’s hydrometers, as ordered 
by the Board. 
l 
2 
3 
4 ■ 
5 
6 
Average. 
Crystallized Citric Acid . . 
42*90 
40*05 
41*74 
39*02 
44*60 
46*90 
42*53 
Gum and Sugar .... 
3*45 
2*39 
3*03 
2*96 
3*67 
3*64 
3*19 
Inorganic Salts. 
2*58 
1*18 
2*38 
2*22 
2*61 
2*73 
2*28 
Total grains per ounce 
48*93 
43*G2 
47*15 
44*20 
50*88 
53*27 
48*00 
Specific gravities . . . 
1*043 
1*040 
1*042 
1*040 
1-045 
1*045 
1*044 
The remainder of the lemons was put aside till the end of May, and again 
examined. The result was thus :— 
1 
2 
3 
4 
5 
6 
Average. 
Crystallized Citric Acid . . 
40*90 
39*65 
39*66 
36*38 
43*93 
45*77 
41*04 
Gum and Sugar .... 
4*33 
2*63 
4*51 
4*25 
3*92 
4-44 
4*01 
Inorganic Salts. 
2*58 
1*18 
2*38 
2*22 
2*61 
2*73 
2*28 
Total grains per ounce 
47*81 
43*46 
46*55 
42*85 
50*46 
52*94 
47*33 
Specific gravities . . . 
1*041 
1*039 
1*040 
1*038 
1*044 
1*044 
1*041 
It will therefore be observed, that as the lemons were kept, and the sum¬ 
mer advanced, the quantity of acid decreased (at first slowly, but at length 
very rapidly) but the specific gravity only suffered comparatively slight dimi¬ 
nution ; the quantity of the juice also remained the same, for eight lemons 
yielded 7 ounces in May as in February. 
On examining the remaining fruit in July the curious fact was ascertained, 
that although the specific gravity was 1*027, yet there was not a particle of 
citric acid. Analysis showed that it had all split up into glucose and car¬ 
bonic acid. 
Since this, the nitrogenous matter in the juice has again set the whole into 
fermentation. The glucose has produced alcohol, and the alcohol acetic acid, 
thus:— 
Oj2 = 4(C 2 H 6 0) -f- 4C0 2 . 
Glucose. Alcohol, 
