Observations on the reaction of the blood of infants with acute intestinal intoxication with the phosphotungstate reagent

In a previous paper 1 on chemical examinations of the blood in cases of infants and children with acute toxic gastro-intestinal symptoms (cholera infantum), it was noted that in some an intense blue color was obtained using only the phosphotungstic reagent after the uric acid had been precipitated with silver lactate. This blue color was often six to eight times more intense than that obtained with the uric acid alone. The reaction was not noted in normal controls. At that time we stated that we did not know whether phenol was the cause of this reaction.

That the so-called phenol reagent (phosphotungstate-phosphomolybdic reagent) first described by Folin and Denis 1 was not specific was shown by Tisdale, 2 Gortner and Holmes 3 and others. They showed that there were other substances which might be present in the blood that gave the same color reaction, hence interfering with the purpose of the original test. A deep blue color is also given by lactic acid, by indol, indol derivatives, protein derivatives and many other substances.

In order to eliminate at least one group of these substances, we determined the amino-acid nitrogen and the peptid nitrogen in some of these cases, using the method described by Van Slyke and Whipple.₄ Although the urea was high in some of these cases the amino-nitrogen and the peptid-nitrogen values were normal, or slightly above normal. One must remember, however, that there may be some toxic protein derivative products or amino acids present which are very toxic in small amounts, although not sufficient to perceptibly increase the amino or pep-tid nitrogen in the blood.