ANTISEPTIC THERAPEUTICS. 
737 
Potassium iodide was administered in two cases of azoturia, 
numbered in our tables 22 and 23. 
In case 23 no lead was found before the administration of 
potassium iodide, but after its use very large tests were ob¬ 
tained. 
In case 22 the amount eliminated was greatly increased. 
Lack of material prevented similar experiments in normal 
horses. For examination of urine about one litre was used in 
each case. For tissue examination one-half the brain, weigh¬ 
ing when fresh about 300 G. or dried 50 G., and of other tissues 
300 G. fresh or 100 G. dry, were used. The tissue or dry urine 
was treated with an excess of nitric acid and allowed to stand 
until the violent reaction was over. 
To the resulting fluid, after concentration to a small bulk, 
28 cc. concentrated sulphuric acid was added and the heat con¬ 
tinued until charring resulted. The fat was not removed. The 
process was then continued by alternately adding nitric acid 
and charring by heat until the organic matter was practically 
destroyed. During the heating a part of the sulphuric acid was 
always decomposed, so that the product (free from nitric acid) 
varied in bulk from 10 cc. to 25 cc., depending in part upon 
the amount of solids present. 
This product was diluted with an equal volume of water 
and the mixture again diluted with an amount of alcohol equal 
in volume to the sulphuric acid and water used. From this 
mixture, after standing several days, the lead was deposited as 
sulphate. The deposit was washed on a paper filter with 50 
per cent, alcohol made acid with sulphuric acid, and was then 
extracted with 10 per cent, ammonium acetate solution. From 
this solution the lead was precipitated as sulphide, and in case 
much iron was present it was removed with very dilute hydro¬ 
chloric acid. The lead was then converted into chloride by 
concentrated hydrochloric acid and removed from the filter by 
hot water. After evaporation the lead chloride was dissolved 
in a few drops of hot water, the solution filtered if necessary, 
and four final tests made, i. e., potassium dichromate, potassium 
