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Quantitative dc arc techniques are described for estimating thallium in two distinctly different types of geological material, granitic rocks and manganese nodules. Thallium is not normally detectable in granite with average concentration of about one ppm. A highly sensitive special procedure of direct excitation has been developed so that this element may now be estimated in granites and related rocks routinely. The thallium concentration in manganese nodules is relatively high (about 50 ppm), but interference from nickel must be drastically suppressed and sample extrusion prevented before a quantitative estimation can be carried out. Details are given of the solution to these problems using K2SO4as the diluent.

1. Clearance of [14C]cholic acid from the systemic circulation was studied in six normal subjects and eight patients with biopsy-proven hepatic cirrhosis. In both groups, during fasting, the curve for disappearance of radioactivity from the serum during the first 100 min after [14C]cholic acid injection was double-exponential in form. During the early phase, clearance was significantly more rapid, and concentrations of conjugated and free bile acid were significantly lower, in normals than in cirrhotics. 2. Radioactivity disappeared from the systemic circulation of normals within 3 h, and neither intravenous cholecystokinin nor the ingestion of food influenced serum radioactivity. Almost all cirrhotic patients had ‘spontaneous’ rises in serum radioactivity, which began approximately 2 h after [14C]cholic acid injection. Cholecystokinin or food given 4–8 h after [14C]cholic acid administration, produced rises. Continuous aspiration of duodenal juice markedly reduced these rises. Reinfusion of duodenal juice into the upper intestine was followed by a rise in serum radioactivity. 3. All rises were due, almost exclusively, to conjugated bile acids. 4. Impaired bile acid clearance in cirrhotics may result from inefficient hepatic extraction of bile acids, increased leakage of conjugated bile acids from hepatic cells and shunting from portal to systemic circulations. The latter factor is probably responsible for elevated, fluctuating, plasma bile acid concentrations in cirrhotic patients.

Evidence of humoral anti-sperm activity was sought in the female partners of 196 couples with unexplained and organic infertility, and in a control group of fifty pregnant women. Two tests were used, sperm micro-agglutination and sperm immobilization. The micro-agglutination test demonstrated little difference in incidence of positive reactions in patients with unexplained and organic infertility and yielded an 18% incidence in the pregnant control patients.The results of the sperm immobilization test showed a clear disparity in patients with unexplained infertility compared with those in the organic infertility and pregnancy groups. A comparison of these results with those obtained by other workers, using the same and other methods, suggests that the sperm immobilization test provides the most reliable single method for the detection of circulating anti-sperm activity with possible clinical significance.