A number of pipetting aids are commercially available which obviate the necessity of filling pipets by oral suction. Most of the commercially available devices involve fitting the pipet into a soft tight fitting bushing and filling by means of either a piston or a rubber bulb. The pipet is then emptied by means of a valve control which permits, it is claimed, a dispensing accuracy of 0.1mL. It is at once apparent that the probable error (10% for a 1 mL. pipet) is considerably greater than is permissible for great precision. In practice these devices are found to be awkward and after a period of use tend to become even more so due to corrosion of the valve and aging of the rubber bushing and rubber bulbs.

A new colorimetric method for the determination of cholesterol has been investigated. It makes use of the relatively stable green color given by a purified digitonin precipitate with the anthrone reagent of Dreywood. Equal precision can be obtained with the new method using 1/10 or less of the quantity of material required for present colorimetric methods.

During the last year we have been attempting to increase our understanding of the significance of the various dilution methods used to measure the extra-cellular fluid. When the dilution methods were first proposed to obtain a measure of the extracellular fluid volume, it was hoped that an agent could be found which would distribute uniformly and exclusively throughout this compartment, which would approach equilibrium rapidly, and which could be measured by simple and accurate procedures. We have turned our attention chiefly to the methods themselves using dogs and non-edematous adults as subjects.

The meteorological control program developed at Brookhaven National Laboratory requires some simple means of classifying atmospheric turbulence so that the dispersion of cooling air from the nuclear reactor may be measured and forecast on a routine basis. The first approach to the problem, was based on the variations of horizontal wind direction as measured by a standard Bendix-Friez Aerovane mounted 355 ft. above ground. The time interval used was one hour. The original system has proven satisfactory in most respects, and is still in daily use.