Whilst we distinguish in an animal body various "tissues" which have special properties and activities, and can be dissected out and delimited--as we could dissect and distinguish the "tissues" (flannel, silk, leather, whalebone, wadding, gold-thread, etc.) making up an elaborate padded, stiffened brocaded, lined, and decorated costume--we find that, unlike what is usual in a man-made costume, all the parts of an animal body (viscera, and their lobes and sub-divisions, the blood-vessels, nerves, muscles, bones, etc.), are covered and separated from one another, and, at the same time, held together by a ubiquitous soft, spongy tissue, consisting of delicate threads and bands, enclosing spaces--some excessively minute and narrow, others larger--in which is a liquid. This is the great packing tissue of the body, and is called "the connective tissue." Its threads and bands have delicate, usually flat nucleated corpuscles (so-called "cells") of transparent protoplasm resting upon them and bathed by the liquid in the fine spaces. The threads and bands are, indeed, the product of the protoplasmic cells, built or "spun" by them, laid down by them as a snail leaves a slimy smear behind it as it crawls. It is not difficult to cut out transparent pieces of this "connective tissue" from a recently killed animal and to examine it with a very high power of the microscope. You may then see the living protoplasmic corpuscles slowly "streaming" and changing shape, and sometimes dividing (one into two) so as to form new corpuscles. I made my first acquaintance with them when I was a student at Vienna with the great microscopist Stricker. We used the glass-clear connective tissue which forms the "cornea" of the eye, cut from a freshly killed frog. In those days the part taken by these cells in inflammation was being discovered, the name "phagocyte" had not been invented, the part played by them and by bacteria in disease and the suppuration of wounds was unknown, and I had the privilege of introducing Lister's earliest researches on aseptic surgery and on the coagulation of the blood to the notice of my friend and teacher.