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IN this study we wished to find what a bird does with all its time each day, and, aided by the literature, to gain some idea as to how and why it distributes its energy as it does among the different activities in its behavioral repertoire. To this end we watched a specific individual Village Weaverbird Ploceus (Textor) cucullatus cucullatus (Muller) from dawn to dusk and counted or timed with a stopwatch the various things it did. In this fashion we watched one male and two females, all individually color-banded, on different days and in different phases of the breeding cycle. The birds studied were captive in a large outdoor aviary in southern California. This situation of course has the disadvantage that the habitat is artificial. It has the advantage that in the confines of the aviary it is possible to watch what a bird does for every minute of the day. This gives a more complete picture than is as yet possible in the field, for example one can count all of the food items an adult bird eats during the entire day and in different phases of breeding. We do not deny that availability of food and nesting materials may have had some influence on activity schedules and rates, though in nature a source of nesting materials, such as tall grasses, often grows next and even directly beneath the colony tree and may sometimes be just about as available as in an aviary. As the food supply in the aviary was held constant, variations in the food situation cannot be held responsible for the great differences noted in certain behavior patterns in different phases of the breeding cycle. Besides being convenient and favoring close observation, aviary studies are at

Serum immunosuppressive activity due to azathioprine was measured using a technique based on the inhibition of spontaneous rosette formation in vitro, in five patients after liver transplantation, and shown to be dependent on liver function. Levels similar to those in controls were found when the plasma-bilirubin was normal whereas in three patients, with various degrees of cholestasis, levels were moderately reduced. Serial measurements in one, showed a close correlation in time between the fall in serum immunosuppressive activity and the development of jaundice. In another patient with severe hepatocellular damage, there was no rise in serum immunosuppressive activity after oral azathio prine. The findings are of importance in relation to the use of azathioprine both in the treatement of rejection of liver transplants and in the control of autoimmune liver disease.