THE TAR ACIDS. 
§ 240 .] 
193 
boiled and distilled with dilute sulphuric acid, and the distillate treated 
as just detailed. 
Like most poisons, carbolic acid has a selective attraction for certain 
organs, so that, unless all the organs are examined, it is by no means 
indifferent which particular portion is selected for the inquiry. Hoppe- 
Seyler applied carbolic acid to the abdomen and the thighs of dogs, 
and when the symptoms were at their height bled them to death, and 
separately examined the parts. In one case, the blood yielded -00369 
per cent. ; the brain, -0034 per cent. ; the liver, *00125 ; and the kidneys, 
•00423 per cent, of their weight of carbolic acid. The liver, then, 
contains only one-third of the quantity found in an equal weight of 
blood, and, therefore, the acid has no selective affinity for that organ. 
On the other hand, the nervous tissue, and especially the kidneys, 
appear to concentrate it. P. G. Menegazzi, 1 from a poisoned rabbit, 
failed to extract from the tissues, etc., more than 29-2 per cent, of the 
phenol administered; which is not surprising, seeing the chemical 
changes it is liable to undergo. 
§ 240. Examination of the Urine for Phenol or Cresol. —It has 
been previously stated (see p. 186) that the urine will not contain these 
as such, but as compounds—viz. phenyl or cresyl sulphate of potassium. 
By boiling with a mineral acid, these compounds may be broken up, 
and the acids obtained, either by distillation or by extraction with ether. 
To detect very minute quantities, a large quantity of the urine should 
be evaporated down to a syrup, and treated with hydrochloric acid and 
ether. On evaporating off the ether, the residue should be distilled with 
dilute sulphuric acid, and this distillate then tested with bromine-water, 
and the tri-bromo-phenol or cresol collected, identified, and weighed. 
Thudichum 2 has separated crystals of potassic .phenyl-sulphate 
itself from the urine of patients treated endermically by carbolic acid, 
as follows :— 
The urine was evaporated to a syrup, extracted with alcohol of 90 per 
cent., treated with an alcoholic solution of oxalic acid as long as this 
produced a precipitate, and then shaken with an equal volume of ether. 
The mixture was next filtered, neutralised with potassic carbonate, 
evaporated to a small bulk, and again taken up with alcohol. Some 
oxalate and carbonate of potassium were separated, and on evaporation 
to a syrup, crystals of potassic phenyl-sulphate were obtained. They 
gave to an analysis 46-25 per cent. H 2 S0 4 , and 18-1 K—theory requiring 
46-2 of H 2 S0 4 and 18-4 of K. Alkaline phenyl-sulphates strike a deep 
purple colour with ferric chloride. To estimate the amount of phenyl- 
sulphate or cresol-sulphate in the urine, the normal sulphates may be 
separated by the addition of chloride of barium in the cold, first acidify¬ 
ing with hydrochloric acid. On boiling the liquid a second crop of 
1 J UOrosi, xxi., 1898. 2 Pathology of the Urine, p. 193. 
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