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An investigation of the spreading of emulsion latex particles on water is described. When the particles are spread with the aid of organic liquids, one particle thick surface films are formed. These films are best characterized by their greater thickness in comparison with conventional monolayer films. Equations are developed to calculate an average diameter of the spread particles from the projected area of an equal mass of monodisperse hard spheres of the same density and the experimental limiting area obtained from the pressure-area isotherm. The limiting areas of four polystyrene latexes studied are 114, 147, 292, and 365 cm 2 /mg; the calculated average diameters are 138, 107, 54, and 43 mμ, respectively. The average diameters as obtained by electron microscopic techniques are: 154, 110, 66, and 46 mμ, respectively.

There have been conflicting reports as to whether the ingestion of fat increases the tendency for the blood to clot, and hence, by implication, the risk of thromboembolic complications in man. In this study the effect of a single meal containing a large amount of fat was compared with that of a practically purely carbohydrate isocaloric meal. Under carefully controlled conditions the clotting time varied widely under fasting conditions, and after both fat and carbohydrate meals the clotting time became longer, shorter, or remain unchanged. The results were unpredictable and although a slight trend toward shortened clotting times was evidenced after the fat meals, the results did not reach accepted statistical standards of probability.

Spread monolayers of normal paraffinic acids, alcohols, and amines were transferred to bare and Parlodion-covered slides. The shadow-transfer technique was used to replicate the transferred monolayers. Examination in the electron microscope revealed that these films were homogeneous, uniform, and continuous. When the transfers were not done under ideal experimental conditions, irregular islands of various size and shape were observed.

Streaming-potential studies were done to evaluate the effect of heparin and also thrombin on the ζ-potential of fibrinogen solutions in contact with capillary surfaces. It is found that unclotted mixtures of thrombin and fibrinogen streamed through clean capillaries have ζ-potentials higher than the fibrinogen in the pH range of 5.5–8. Polymerizing mixtures have ζ-potentials slightly below those for fibrinogen. Heparin is found to increase the ζ-potential of fibrinogenated Teflon and Pyrex capillaries. It is demonstrated that the previous history of the capillary surface influences the extent of these increases. Higher ζ-potentials for mixtures of heparin and fibrinogen are obtained with clean surfaces than with coated capillaries at several pH values. The effect of increasing the heparin concentration in the mixtures streamed through clean capillaries for several fibrinogen concentration levels at pH 7.4 was investigated. It is observed that the ζ-potentials increase to a maximum and remain constant thereafter as the heparin concentration is increased. These results are discussed in terms of electrostatic interaction and a mass-action mechanism.

Zeta-potentials for Pyrex surfaces in contact with solutions of human and bovine fibrinogen at different concentrations and over a wide pH range have been determined by the streaming-potential technique. The fibrinogen-Teflon interfacial potential was also evaluated as a function of fibrinogen concentration. A new direct-current amplifier of high input impedance and sensitivity is used to measure streaming potentials for solutions whose specific conductances are greater than 1 × 10 −3 mhos/cm. The preparation of Parlodion-coated Ag-AgCl electrodes for use with solutions of high protein concentrations is described. It is found that the ζ-potential for the fibrinogen-Pyrex interface decreases as the concentration of protein increases. The ζ-potentials for human and bovine fibrinogen change from positive to negative values as the pH is varied from 3.2 to 8.6. It is observed that the zero ζ-potential for both human and bovine fibrinogen solutions (κ ca . 3 × 10 −4 mhos/cm.) occurs at the same pH, namely 5.8. This value is also the pH for the isoelectric point. It is also found that fibrinogen solutions, at constant pH and ionic strength, have lower ζ-potentials in contact with Teflon surfaces than with Pyrex. It is demonstrated that coatings of fibrinogen on Teflon and Pyrex surfaces are tenaciously bound.

• In any disturbance of liver function, whether due to acute infection or to chronic liver disease, where significant areas of hepatic cells undergo necrosis, elevations of the serum transaminase level may be expected. As the liver parenchyma heals and the liver cells regenerate, normal levels are obtained. Normal serum transaminase values have been found to range from 5 to 40 units; with Laennec's cirrhosis the levels were from 13 to 286 units, in biliary cirrhosis from 57 to 330 units, and with viral hepatitis from 540 to 1,890 units of activity. While there has been no constant correlation with other usual liver-function tests, it appears that any process causing death of enough liver cells should increase the serum transaminase activity.