20 
N. C. Agricultural Experiment Station 
Determination oi Uric Acid 
Take ten grams of thoroughly mixed ground feces, place in a 250 cc beaker and 
treat with 100 cc. of 95% alcohol. Filter through paper and wash twice with 30 cc. 
of alcohol, then wash three times with ether and allow to dry. This removes the great- 
er nart of the coloring and fatty matter. The residue when dry is returned to the 
beaker. One hundred cc. of 5% solution of HC1 is added and set in a refrigerator over 
The following morning the material is filtered through paper and washed twice 
with cold water returned to the beaker with 100 cc. of water and enough piperidine 
added to dissolve the uric acid. A few drops of phenolphthalem were added to the 
solution in order to determine the amount of alkali necessary to dissolve all the unc 
acid also the disappearance of the white particles from the bottom of the beaker in¬ 
dicates complete solution. It usually requires from one-half to three-fourths of an 
hour heating on the water bath with frequent stirring to effect complete solution. 
After the white particles all diappear and the solution remains alkaline it is passed 
through a coarse linen filter into a five hundred cc. graduated flask, washed thorough ¬ 
ly with hot water, squeezing out, filtered two or three times to fac'htate washmg, cooled 
and made up to the mark and thoroughly mixed. The solution is then allowed to 
“tele until the fine particles which passed through the cloth settle out, leaving a clear 
solution which can be drawn off. The solution is allowed to settle over night so 
it will be clear in the morning. . , .,* upi 
Fifty cc. portions, representing 2 gms. of the feces, are taken, made acfo with HC1 
evaporated on a water bath to 25 cc. and set in a refrigerator over night, or better 
stiUfor twenty-four hours. Then filter through a 597 S. & S. filter paper on a Buc - 
ner's funnel 50 mm. in diameter, under pressure, wash three times with cold water, 
then with absolute alcohol, and lastly two or three times with ether to:remove any 
trace of remaining fat. The uric acid is thus collected on a very small filter pap 
which is transferred to a beaker, boiled with 35 cc. of distilled water an i ** ® 
with N—10 piperidine solution. It is very necessary to complete the end reactio 
with the solution as near the boiling point as possible, or concordant results canno 
be attained. All determinations are run in triplicates The first tit-tion .made 
roughly to find out the approximate end point. In titration, as t P 
being reached, the beaker is again put over the flame and brought to boiling point, 
then titrated to completion. „ . - n 
To test the accuracy of the method pure uric acid is added to feces that conta 
none. The average determination in our case gave 98.2 percent of acid recovere . 
The piperidine solution is standardized with uric acid which is purified by twice 
recrystalizing and found practically pure. 
THE PREPARATION OF PIPERIDINE FROM PYRIDINE 
AND SODIUM 
Action of metallic sodium in solution of pyridine in absolute alcohol. 
Absolute alcohol was made from 95% alcohol by dehydrating it with calcium oxide 
and redistillation at 80 degrees to 90 degrees C. 
One hundred cc. pyridine was dissolved in 1800 cc. of absolute alcohol and 156 gms. 
of metallic sodium gradually added till all was dissolved. Sodium ethylate was re¬ 
moved by filtration three times during the adding of the sodium. 
Excess alcohol was distilled. Portion of distillate caught at 80 degrees to 82 
degrees C. and was saved for further use. 
