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To 5 cc. portions of Folin-Wu filtrate were added 10 drops of a solution containing 6.4% NaH2PO4and 17.9% Na2HPO4. These were then inoculated with a strain of an organism culturally and morphologically typical of Bacillus coli communis.After 24 to 48 hours incubation the residual reduction was determined by the technique of Folin and Wu1modified as follows: Several dilute standards ranging from an equivalent of 0 to 0.020% in terms of the original blood were treated in the same manner as, and simultaneously with, the unknown solution. The color of the latter was then compared directly without dilution and without the aid of a colorimeter with the color given by the standards. The readings of about 100 determinations on whole blood ranged from slightly below 0.010 to somewhat over 0.020%, with the greater part of the figures lying between 0.015 and 0.020%. Plasma values were one-third to one-fifth of those obtained without removing the cells. If varying amounts of solution were used together with sufficient water to make the volume 2 cc., the results were proportional to the amount of filtrate present. When glucose was added to such incubated material immediately before the analysis the sum of the added glucose and the residual reducing power was found by the standard technique of Folin and Wu.2If glucose was added and incubation continued the added glucose was destroyed in 12 to 18 hours. If the incubation of such filtrates was continued for several days there was sometimes a very slight further decrease in reducing power which may have been associated with contamination, as it was not observed when the solution was autoclaved before inoculation. In solutions of pure glucose similarly treated the reducing power decreased much more slowly and the opacity indicated the presence of much fewer organisms.

Gmelin's test for bile pigments was carried out on all specimens of urine submitted to the laboratory during a period of a little more than 2 years. Approximately 50,000 specimens were examined during this time, and a positive test was obtained in 476 specimens from 308 subjects. Most of the patients treated in this institution are suffering from chronic diseases and are of fairly advanced age. Since daily specimens were obtained from diabetic patients and urine from those on the surgical service was examined routinely 3 times a week these 2 groups have an undue prominence in the series. The approximate concentration of urobilogen in the specimens giving a positive Gmelin test was determined by the method of Wallace and Diamond.1Normal urines show a positive test by this method when diluted 1 to 10 or 1 to 20 with water, but give no color when dilution is greater. In our series 142 specimens, or less than a third of the total, fell into this range. There were 54 specimens from 18 patients which gave a negative Wallace and Diamond reaction, and it seemed probable that these could be adequately explained by failure of bile to enter the intestine, as the diagnoses indicated the certainty or the possibility of the presence of lesions obstructing the bile ducts in most cases. Only 24 specimens from 22 patients showed a positive reaction which became negative when the urine was diluted with 9 parts of water. Over half of the analyses (256 specimens) gave results which were high, and such figures were obtained at some time or other upon 198 patients, or approximately two-thirds of the entire series. In general the diagnoses on these patients offered no adequate explanation of the findings.

In 316 specimens submitted for the determination of the degree of pigmentation of the serum by the method of Meulengracht1the direct diazo reaction described by Van den Bergh2was also carried out. The table shows the relationship found between the results of the 2 tests. When the icteric index was high practically all specimens gave a positive diazo reaction, but when it was low the number of specimens which gave this result was much smaller. The time required for the reaction to become positive also varied with the intensity of the yellow color (amount of bilirubin present). The time was decidedly shorter in the average specimen with a high index than when the index was low. The occurrence of an immediate reaction seemed in most instances to be a part of the expression of this decrease in the reaction time rather than of some independent phenomenon, such as a chemical difference in the nature of the bile pigment present. There were a few rather conspicuous exceptions to this orderly arrangement, and the authors believe that the presence of substances, other than bile pigments, which give the diazo reaction must be considered as a possible explanation for them.

Charts and tables showing relationships between the urinary reaction and phosphate concentration in short period experiments on subjects taking normal diets and eating a standard meal were prepared. The experimental technique has been described elsewhere.1The Bell-Doisy method was used in determining the phosphate concentration.2When equal reactions were found on 2 specimens of urine obtained at about the same time the actual pH values were usually fairly low, but there was a second, smaller group in which they were more alkaline. The reactions of relatively few specimens fell between pH values of 6.0 and 7.0. The authors believe that the former, larger group, probably represents a true physiological constancy of the reaction, while the smaller one where the reaction is more alkaline they think frequently contains instances in which those changes in the reaction of urine which take place after a specimen has been voided3have taken place under approximately constant conditions, and have produced a constancy of reaction which may have little physiological significance. The phosphate concentration was much higher in the more acid than in the more alkaline group.Further study of the material brought out the following points: 1, when the reactions of 2 specimens of urine obtained from the same patient differed by 0.2 pH or less the average of the means of the phosphate concentration in the urine was about 20% higher than in the whole series; 2, when the reactions of 2 specimens differed by more than 2.0 pH the average of the means was 50% lower than in the series considered as a whole; 3, when the mean phosphate concentration was high very few specimens showed differences in reaction which were greater than 0.2 pH; 4, when the mean phosphate concentration was low about half of the specimens, even from patients with achlorhydria, showed differences in reaction greater than 0.2 pH; 5, the average mean pH was lower when the phosphate concentration was low than when it was high; 6, in many individual experiments there was little or no correlation between changes in reaction and in phosphate concentration; 7, the average phosphate concentration was higher in achlorhydria, possibly due to the small hourly volume of urine excreted, than it was in a short control series.

A fairly large number of persons show a marked urinary alkalinity which persists through the morning period. This alkalinity may be independent of diseases of the kidneys and urinary tract, and of the type of diet preceding the test. It may not be present during the afternoon period. It probably represents an unusual adjustment to waking conditions, exaggerated in most instances by the secretion of hydrochloric acid by the stomach.The reason why such an adjustment is different in these cases from that more commonly observed did not appear in a study of the type of patient upon whom the results were obtained. It seems to the authors that the following general statement covers the fact: there are 2 methods of compensating for a tendency towards alkalosisthrough the urine and through the lungs. In these subjects the compensation is accomplished through the kidneys to a greater extent than is the case in most persons.