It consists essentially of a number of minute corpuscles or plastids, the protoplasmic substance of which is impregnated with a green coloring matter.
These are peculiar bodies which are found in the prostate, in the central nervous system, in the lung, and in other localities, and which get their name from being very like starch-corpuscles, and from giving certain colour reactions closely resembling those of vegetable cellulose or even starch itself.
The white blood-corpuscles are produced in the follicles at the base of the intestinal villi.
The red blood-corpuscles are invariably oval disks, with a central nucleus which causes a slight swelling; hence they are oval and biconvex.
It contains a colourless fluid, with flat, oval, nucleated corpuscles, as a rule colourless, but in some cases tinged with yellow or red haemoglobin.