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SummaryIn small-scale laboratory experiments with sulphamate baths, alloys of iron with nickel, cobalt, cadmium and zinc have been deposited over a wide composition range. The effect of variables on alloy composition, cathode efficiency and cathode potential has been investigated and optimum operating conditions established for each alloy. The cathode efficiency is close to 90% under favourable conditions, and the limiting current density is quite high, 10 to 25 A/dm2 depending on the alloy. The performance of alloy anodes of nickel-iron and cobalt-iron is quite satisfactory; single metal anodes can be used for the other two alloys. In the case of iron-zinc deposition, there are sudden changes in plate composition for a small variation in the current density, corresponding to changes in the phase of the deposited alloy. X-ray diffraction studies show that the cadmium-iron deposit is a mixture of the two metals.

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.

Results of C.R.P. test evaluation as an index of disease activity are reported in 10 cases of acute rheumatic fever, 18 cases of rheumatic heart disease and three cases, of rheumatic chorea. C.R.P. test seems to be a sensitive index of disease activity and a reliable guide to the management of cases. It faithfully reflects the activity and is not affected by drugs, a distinct advantage over E.S.R. However, being non-specific, it is not very helpful in diagnosis.

Department of Chemistry,Harcourt Butler Technological Institute, Kanpur (Manuscript received 27 May 1970; accepted 3 April 1972) Chalcones. Part III: Potential Germicides Derived from 4-Hydroxy-3-Nitro-1/ Acetonaphthone&nbsp