The survival rate,p, of a measured inoculum ofStaph. aureusin a standard volume of denbrinated blood, is a reliable quantitative measure of the bactericidal power of blood. The number of viable organisms in the inoculum and in the blood-bacterium mixture may be estimated with the necessary accuracy by counts of colonies developing from measured volumes of the fluids let fall on to the surface of solid media. Fildes' agar was the most suitable medium for this surface-viable count, and was selected on the basis of four criteria; of the media tested it yielded the highest counts, and the counts conformed most closely to a Poisson series; and on it the mean colony size was maximum, and the coefficient of variation of colony size was minimum. On this medium, the close conformity of the separate count values to a Poisson series enabled the standard error of the survival rate to be determined from a simplification of the general expression for the standard error of a ratio.The number of colonies growing from a sample of a blood-bacterium mixture may be reduced, not by killing of the individual cocci, but as a result of their aggregation either by agglutinins in the blood, or in the cytoplasm of leucocytes that are phagocytic but not bactericidal. It appears that these mechanisms are unlikely to operate in blood-bacterium mixture containing relatively few organisms; in such mixtures the survival rate is a reflexion of the killing power only.The immunological significance ofphas not been investigated, but the range of values for healthy human adults differs significantly from that for sufferers from chronic staphylococcal infection. Moreover, by the technique employed differences may be detected between individual values ofpthat cannot reasonably be attributed to technical or sampling errors.

A substantial increase in capillary permeability is a feature of acute inflammation in bacterial infections. The present investigation is part of an attempt to prove an old hypothesis, namely, that this increase in permeability is mediated by histamine. A comparative study was made of histamine, of the histamineliberator 48/80, a condensation product ofp-methoxyphenylethylmethylamine and formaldehyde (Baltzly, Buck, de Beer & Webb, 1949), and of leukotaxine (Menkin, 1936(Menkin, , 1938a.In animals with a recently injected vital dye in their blood, the intradermal injection of substances that increase permeability of the blood vessels is followed by an accumulation of dye at the site of injection, presumably due to the passage of an excess of dye-stained plasma into the tissue spaces. When the blood flow and the vascular bed of the skin are relatively constant, differences in the size and intensity of stained areas of skin reflect differences in vascular permeability, and may be used to investigate the properties of substances that increase permeability in this way. Our work was confined to the skin of guinea-pigs, partly because much is already known about skin reactions to toxins and other inflammatory agents, and partly because it is a tissue readily studied in the intact and unanaesthetized animal-an important consideration with phenomena which, like the passage of dye through vascular endothelium, are peculiarly dependent on the state of the blood vessels in the tissue under test. MATERIALS AND METHODSAlbino guinea-pigs, 300-450 g in weight, were used throughout. The skin of the trunk was depilated, after clipping away the hair, by a paste consisting of wheat flour, 350 g; talcum powder, 350 g; barium sulphide, 250 g; Castile soap powder, 50 g; and water. The depilated area was thoroughly washed with warm water.Detection of increawed permeability. Neither the intradermal injection nor the pricking-in of histamine or 48/80 produce in the depilated skin any measurable reaction indicating change in

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The existence of small numbers of schizophrenia patients with superior ability in specific cognitive domains is implied by meta-analytic evidence as well as by occasional empirical reports. The authors identified 25 patients with superior (i.e., > or =90th percentile) ability on the Vocabulary subtest of the Wechsler Adult Intelligence Scale 3rd edition (Wechsler, 1997). These cognitively advantaged patients were compared with 22 healthy participants performing at the superior level and with 126 schizophrenia patients and 50 healthy participants scoring below the superior range. Verbally superior schizophrenia patients and verbally superior healthy participants had similar cognitive profiles and life skills performance, but diverged markedly in terms of independent "real-world" functioning. Verbally superior patients significantly outperformed more typical patients in other aspects of cognitive performance, life skills, and support requirements. However, severity of positive and negative symptoms was equivalent in the patient groups. Detailed biobehavioral study of cognitively exceptional patients may offer new insights into mechanisms mediating psychotic disorders.