78 XI.-On, Citric Acid as a Constituent of the Juice of Unrt$e Xulberries. By C, R. ALDER WRIGHT, D,Sc., and GEO. PATTERSON. THROUGH the kindness of Dr. Hardwicke, coroner for Middlesex, we obtained a quantity of the juice of mulberries grown in his garden a t Hendon. The fruit did not appear to ripen this year as fast as usual, so that, before it was fully ripe, an early frost almost stripped the tree of leaves, leaving bushels of berries not quite fit for eating. The juice of these was expressed, and constdxted a somewhat turbid light brown fluid of very acid taste. On keeping in a loosely corked phial, it became mouldy on the top, and developed a small quantity of alcohol. On qualitative examination, it was found to contain a considerable amount of mucilaginous matter, precipitable by addition of an equal volume, or rather more, of strong alcohol. The filtrate from this, when boiled down so as to expel the alcohol, and neatralised with ammonia, gave no precipitate with calcium chloride in the cold, but on boiling for half an hour threw down a sandy calcium salt.The concentrated filtrate from this (containing excess of calcium chloride and rendered alkaline by ammonia) deposited no more precipitate on further boiling, butl on addition of alcohol an amorphous lime-salt was thrown down. From these observations it appears that whilst oxalic and tartaric acids were absent, or present in insignificant quantity only, citric acid was present to a considerable extent, and apparently also malic acid. A volatile acid, presumably acetic acid, was also found in minute quantity.Fehling’s solution was easily reduced on boiling. To determiue approximately the citric acid, a known quantity of juice was boiled with ammonia and a recently boiled and filtered mix- ture of calcium chloride and ammonia, until no further precipitate was occasioned in the filtered liquid on further boiling ; the precipitated calcium citrate was collected and washed with a minimum of water till the washings were free from chlorine, then dried, and determined as calcium carbonate by ignition, and treatment of the residue with ammonium carbonate. The filtrate was treated with twice its volume of alcohol, and the precipitated gelatinous lime-salt collected, washed with 60 per cent. spirit, and weighed as carbonate. The ash left on incineration was dissolved in hydrochloric acid and treated with am- monia, whereby a precipitate mainly consisting of phosphate of calcium was thrown down ; the lime in the filtrate from this was determined as oxalate, and the potash in the filtrate by platinic chloride after evaporation to dryness and ignition.The following numbers were obtained :-WRIGHT AND PATTERSON ON CITRIC ACID, ETC. 79 Grams per litre. Citric acid, 25 C.C. gave 0.524 CaCO, = 0.6707 C6H807 = 26.83 Malic acid, ,, 0.146 ,, = 0.1956 C4H605 = 7.82 Glucose, = 0.0685 glucose = 2.74 Ash, 0.0330 was phosphate of lime, &c., pre- 0.0140 was CaC0, .................... 0.56 0.10G5 ,, N&CO3, silica, and matter un- 25 C.C. reduced Cu20 containing 0.1220 Cu 25 C.C. gave 0.2350 total residue, of which cipitated by NH,.............. = 1.32 0.0815 ,, K2C03 .................... 3.26 determined ................ 4.26 9.40 Other constihents, mucilage, pectin, &c., &c. ........ 23.3 7 0,2340 Total s0Zid.s (25 C.C. gave 1.754 grams after drying for about 24 hours at loo", till almost constant in weight).. .................................... = 70.16 0.27 anhydrous citric acid, C6HS0, .................. 28.14 In order to confirm the presence of citric acid, the juice was boiled with marble powder, and the organic lime-salt formed washed and decom- posed by sulphuric acid. In this way citric acid was readily obtained. The calcium salt of the acid thus isolated was prepared by neiitralising with ammonia, adding a filtered boiled mixture of calcium chloride and a<mmonia, boiling, and well washing the sandy precipitate.After drying at 100" till constant, the following numbers were obtained :- 0.3950 gram dried at 150-160" lost 0.0330 = Calculated for ( C6H507)2Ca3,'LH20. ....... = 6.74 ,, 0.361 gram of dried residue gave 0.293 CaS04 .......................... Ca = 23.87 ,, Calculated for ( C6H507)2Ca3 ............ = 24.09 ,, - VoZatiZe acid (reckoned as acetic acid) .............. TotaE acidity, determined by titration and reckoned as 8.35 per cent. According to Warington (this Journal, 1875, 925), citrate of cal- cium dried at 100" contains 5.91 to 7.68 per cent. of water of crystal- lisation, or approximately 2H20. According to some text-books, however, the salt when dried at 100" is (C6H507)2Ca3,H20. It results from these numbers that whilst unripe mulberry juice is not as rich in citric acid as lemon and lime juice (which contain 8 to 12 ounces per gallon, or 50 to 75 grams per litre of crystallised acid, or 46 to 68 grams per litre of anhydrous acid, C6H807-Warington,80 TILDEN ON THE RYDROCARBONS OBTAINED FROM Zoc. cit.), it is still sufficiently rich to be a notable source of t,hat acid. From this circumstance, and the presence of considerable quantities of potash, it seems probable t<hat the juice of imperfectly ripe mulberries may be found to be vahable as an antiscorbutic, and as a substitute for lime juice.