TRANSACTIONS OF THE SECTIONS. 123 



voiding witli hydrochloric acid. 2"5 per cent, of that acid was added to each ; 

 and as it had been observed that uric acid was lost by decautation, however 

 careful, the portions of urine operated upon were entirely filtered, and the water 

 with which the precipitates were washed was acidified with acetic acid. The 

 secretion of mucus being now a good deal in excess, the quantitj* of alkali taken 

 was reduced — ^for five days to 300 grains of the citrate in twenty-four hours, for 

 eight days to quantities varying from 270 to 240 grains, and for thirty-five days 

 more (wdth the exception of three days, on account of diarrhoea and bleeding) 

 to quantities varying from 285 to 120 grains. The details of these experiments 

 were given in the paper * ; but it may be enough to mention here that no propor- 

 tion could be observed between the determinations of alkalinity and those of the 

 accompanying uric acid. Twenty days, in which the alkalinity of twenty-four 

 hours varied from 19-2 to 40'3, gave an average of uric acid 7'94 grains ; whilst 

 fiifteen days, when the alkalinity was from 191 down to 1'4, gave an average of 

 uric acid 8-08 grains — a fact which would have shown that the alkali had exercised 

 no action on the calculus, in case the determinations of the uric acid could be 

 depended upon, and in case the alkaline treatment did not cause a diminution of 

 the uric acid secreted. The latter point coidd only be ascertained by a course of 

 experiments in cases free from calculus ; the former point the author proceeded 

 to investigate. He found that the quantity of uric acid precipitated from the 

 urine was diminished by dilution, and augmented by concentration pre\ious to the 

 addition of tJie hydi-ochloric acid. In forty comparative experiments, the two 

 extremes of excess in the concentrated over the natural urine were 1-08 and 

 4-13 grains, in the last fifteen of which the urine was reduced to a standard volume 

 of 6 or 3 fluid-ounces, according as half or quarter of the urine was employed ; the 

 average difference was 3-03; in the former twenty-five, reduced to the above pro- 

 portions, the average excess in the weight of the precipitates was 309 grains. The 

 determinations were further improved by the adoption of the following method : — 

 a fourth of the m-ine of twenty-four hours was evaporated to 3 fluid-ounces ; it 

 was treated with a mixture of hydrochloric acid and alcohol in equal parts, each 

 being 2"o per cent, of the quautitj' of urine emploj'ed ; the precipitate was washed 

 with alcohol (methylated spirit), and then with equal parts of acetic acid and 

 water. The colouring-matter and phosphates &c. were thus removed, and the 

 lU'ic acid was of a light colour and completeh', though confvisedly, crystalline. 



The advantage which this method possesses over those heretofore in use is shown 

 in the experiment which foUows : — In urine having an acidity of 5 grains per pint, 

 the nitric-acid method gave 1-16 gi-ain of impure lu'ic acid ; the ordinary* hydro- 

 chloric-acid method 5-53 grains, the method above described 9-90 grains of uric acid. 

 The proportion of alcohol to the hydrochloric acid was then increased to the bulk 

 of the evaporate. The urine voided in twenty -four hours (35 fluid-ounces), of which 

 the Jicidity =15'7 grains of carbonate of potash, was neutralized and divided into 

 3 parts ; No. 1 (117 fluid-ounces) was evaporated to I'o fluid-ounce ; an equal bulk 

 of alcohol was added with 23 drachms of hydrochloric acid. To No. 2, 17-5 grains of 

 carbonate of potash were added, and it was then treated like No. 1. No. 3 was 

 treated like No. 2, but with the addition of 3 grains of uric acid dissolved in car- 

 bonate of potash. The three precipitates were severally washed, first with alcohol, 

 and lastly with equal proportions of acetic acid and water. The result was fol- 

 lows : — 



No. 1. No. 2. No. 3. 



Uric acid 6'97 G-51 962 -3 = 6-02 grains. 



The urine of twenty-four hours (35-5 fluid-ozs.), of which the acidity =10 gi-ains 

 of carbonate of potash per pint, was neutralized and divided into four parts. No. 1 

 was treated in all respects Hke No. 1 of the above series. No. 2 was similarly 

 treated with the addition of 30 grains per pint of carbonate of potash neutralized. 

 No. 3 was treated like No. 2, with the addition of 2 grains of uric acid dissolved in 

 carbonate of potash. No. 4 was evaporated only to 3 fiuid-ounces ; the alcohol 

 added was only 1-7 fluid drachm ; in other respects it was treated like No. 2 ; 



* The details here mentioned are to be found in the ' Medical Times and Gazette ' 

 (vol. ii. p. 482). 



