EMIGKATION OF LEUCOCYTES
blood corpuscles intermixed with a certain number of polynuclear white blood corpuscles; and above this a layer made up predominantly of white blood corpuscles these last in the front ranks consisting almost exclusively of small and large mononuclears. The blood now clots. And this gives in the upper half of the tube a clot consisting of fibrin without any formed elements let us call this the white clot and in the lower half of the tube a clot let us call this the red clot which holds all the corpuscles in its meshes. When a chemotactic stimulus now comes into application from above, the white blood corpuscles will come out from the red clot and will travel upwards through the meshes of the white clot afterwards maintaining their positions so as to allow of our making measurements and enumera- tions. We will now pass to the details of the technique.
DETAILS EELATING TO APPAEATUS AND PEOCEDUEE.
With regard to apparatus, all that is required is a supply of flat capillary tubes. By using flattened capillary tubes we obtain a thin clot, which can more easily be examined under the microscope.
We make these tubes and they may conveniently be called emigration or chemotactic tubes either out of a small test-tube, or out of a length of fairly