some believe, is to keep the nostrils damp, so that the inhaled air may be moist, 26 and likewise to favour the power of smelling. But another, and at least equally important function of tears, is to wash out particles of dust or other minute objects which may get into the eyes. That this is of great importance is clear from the cases in 26 Bergeon, as quoted in the 'Journal of Anatomy and Physiology,' Nov. 1871, p. 235. N [page] 178 which the cornea has been rendered opaque through inflammation, caused by particles of dust not being removed, in consequence of the eye and eyelid becoming immovable. 27 The secretion of tears from the irritation of any foreign body in the eye is a reflex action; -- that is, the body irritates a peripheral nerve which sends an impression to certain sensory nerve-cells; these transmit an influence to other cells, and these again to the lacrymal glands. The influence transmitted to these glands causes, as there is good reason to believe, the relaxation of the muscular coats of the smaller arteries; this allows more blood to permeate the glandular tissue, and this induces a free secretion of tears. When the small arteries of the face, including those of the retina, are relaxed under very different circumstances, namely, during an intense blush, the lacrymal glands are sometimes affected in a like manner, for the eyes become suffused with tears. It is difficult to conjecture how many reflex actions have originated,