1. The concentrations of plasma total and unconjugated bilirubin and of serum nonesterified fatty acids (NEFA) have been measured in two healthy subjects during fasts of up to 21 h. 2. Fasting was either continuous or interrupted by various procedures that altered the concentrations of NEFA and total bilirubin. 3. When NEFA concentrations were increased by the administration of noradrenaline, heparin or caffeine, bilirubin concentrations also rose. 4. When NEFA concentrations were lowered by insulin, bilirubin concentrations fell. 5. Meals of 3-138 kJ and more, taken during the fasting period, lowered total bilirubin and NEFA concentrations in both subjects, whereas the effects of smaller meals were less consistent. 6. These studies demonstrate a statistically significant correlation between total bilirubin and NEFA during uninterrupted fasting and an association between these variables under other experimental conditions. They suggest that the control of bilirubin concentrations in the blood is linked to lipid metabolism.

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The release of fatty acids and glycerol from adipose tissue of obese diabetics and obese controls has been studied in relation to the fall in plasma fatty acids during a glucose tolerance test. Adipose tissue was taken at zero-time and 1 h after an oral glucose load (50 g). Obese diabetics released more fatty acids from adipose tissue than obese controls (p < 0.001), whereas glycerol release was similar in the two groups. The percent reduction in release of fatty acids from adipose tissue of obese diabetics during a G. T. T. was significantly less than obese controls (p < 0.02), as was the percent fall in plasma fatty acids (p < 0.02), whereas the percent reduction in glycerol release from adipose tissue was similar in the two groups. In addition the percent fall in plasma fatty acids during a G. T.T. correlated with the percent reduction in release of fatty acids from adipose tissue (p < O.O5), but not with release of glycerol; and the increment in plasma insulin from zero-time to lh during a G.T.T. correlated with the percent reduction in fatty acid release from adipose tissue (p<0.01). Finally, the plasma insulin at lh of a G.T.T. correlated inversely with the release of fatty acids from adipose tissue (p < 0.05), but not with the release of glycerol. The data is consistent with the view that the plasma fatty acids falI during a G.T.T. due to re-esterification of fatty acids rather than due to an antilipolytic action of insulin.

Several explanations have been proposed to explain these divergent results-failure to define the population being studied; differing, possibly incorrect methods of sample collection; failure to obtain truly "normal" subjects for control purposes, etc. To avoid these various criticisms we have studied a group of normal, asymptomatic women who had not been hospitalized and compared the findings with those in three groups of patients, the pattern of whose illness had been carefully defined by long-term follow-up in a specialist urinary infection clinic. To reduce sampling errors and to define the regular carrier state of these women each was studied weekly for five or six weeks. To exclude the possible influence of recent infection (Marsh et al., 1972) or antibiotic treatment or a changing state before subsequent infection (Stamey et al., 1971) all the patients were known to have had no bacteriuria or antibiotics for six weeks before the study and no bacteriuria during or within six weeks of completion of the study.The results show no difference in the introital carriage rate of E. coli between normal subjects and patients referred with a history of previous urinary infection whether they were subsequently shown to be intermittently bacteriuric, symptomatic and abacteriuric, or asymptomatic and abacteriuric. A small difference in periurethral carriage of enterobacteria in general was observed between normal subjects and the patient groups though there was no difference between the patient groups. Thus it does seem that patients with a previous history of urinary infection may have a slight change in the overall periurethral colonization as compared with normal women but that there is no difference in this respect between those who are subsequently intermittently bacteriuric and those who are persistently abacteriuric. Furthermore, though E. coli was the most common cause of bacteriuria in our patients no difference in the periurethral carriage rate was observed between the normal subjects and the three patient groups. There was also no difference in the recovery rate or persistence of particular E. coli serotypes.When these results are compared with other reports it must be noted that slightly differing techniques are used. Thus Stamey et al. (1971) studied clean-catch urethral urine samples (labelled VBJ) and samples from the vaginal vestibule, Bailey et al. (1973) studied swabs from the external urethral meatus (periurethral swabs) and vaginal vestibule, and Cox et al. (Cox, 1966;Cox et al., 1968) obtained urethral specimens using a specially designed instrument. We have previously used the term "introital" swab to define what is more correctly a periurethral swab. We have also previously shown and subsequently confirmed that colony counts of the same organism are obtained in the same proportion of instances from urethral urine (vB,) and periurethral swabs in normal women and patients alike.By dividing patients into "persistent", "intermittent," and "non-") carriers of introital bacteria on the basis of sw...

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