In a report representing sixteen years' direct study of the circulating blood, Knisely and associates1 tell of observations on organs of experimental animals and on the bulbar conjunctivas of healthy and diseased human subjects. Studies of living organs were made in frogs, mice, rabbits, dogs, monkeys and other laboratory animals. Parts of organs were transilluminated by lightconducting fused quartz rods and were studied under the microscope with a magnification of sixteen to six hundred times. Structure, dimensions and behavior of blood and blood vessels were observed. Studies in human subjects were made on unanesthetized bulbar conjunctivas with binocular dissecting microscopes, using oblique illumination of universal slit lamps or ophthalmoscope light.
In healthy animals and human beings Knisely and his co-workers concluded that circulating red blood cells are not agglutinated but tend to repel each other slightly. Rouleau formation does not take place in carefully handled tissues. The normal red