Page:Life in Motion.djvu/109

in whichi no nervous tissue can be detected, manifests contractility.

Let us examine this diagram showing a Fig. 41.—Drop of human blood. a, coloured or red corpuscle, showing clear spot in centre, or a′, dark spot in centre, according to focus; b, b, b, colourless corpuscles, or leucocytes; b′, red corpuscles in rouleaux. 300 diameters. drop of human blood, as seen by a microscope magnifying about three hundred times. You Fig. 42.—White blood corpuscles in frog's blood, magnified 560 times. Changes of form observed during ten minutes. Numbers represent minutes from the beginning of the experiment. see the red corpuscles in great numbers, but here and there you will observe a few larger ones. These are leucocytes or white blood