ABSORPTION FROM THE SKIN.
Now it is easy to fail to estimate the import ance of the lymphatic system, and perhaps its significance will be best understood by a few examples. Let it be repeated that lymphatic channels exist in every organ and tissue; they abound in the skin. Now suppose a pin or some sharp instrument with a dirty point is introduced into the skin. The poisonous ma terial left among the moist tissues cannot fail to be carried with the lymph into a lymphatic channel. It will be carried to a lymphatic gland, and may be there intercepted, or may filter through the gland and gain access to the blood. All this may happen in a very short time, and thus it is evident how blood-poison ing may be the result of a very small wound. Even though the material introduced into the skin be not sufficient in quantity or in violence to poison the blood, it may produce other effects. It may irritate the vessels along which it is carried, and inflammation result ; and then the presence of lymphatics in the skin is speedily revealed by the appearance of fine red lines, painful to the touch, which mark the track of the inflamed vessels, while the skin in the neighbourhood of the vessels is wollen and glazed. In the same way the_fiegon may act upon the gland. It sometimes seems to spend its strength on the gland, which becomes in flamed, swollen, and in the end an abscess may be formed, or, even if that does not result, a hard swollen mass remains to mark the attack.
'rake another example — the occurrence of hard, s wol len glands, popularly called is common in children, particularly at the side of the jaw and in the neighbourhood of the ear. Of course something may have directly injured the gland to make it swell in this way, but if what has been said has been understood, it will at once occur to anyone that the swelling of the gland may be due to some irritating matter brought to it by a lymphatic vessel from some part a little removed from the gland. Under
such circumstances, if one knows from what part of the body the lymphatic gland receives its lymphatic vessels, one may examine the whole district to see if in any part of it some irritation is present to account for the enlarged gland. This will be again referred to in speak ing of inflammation of glands.
Advantage is taken of the absorbing power of the lymphatics to introduce medicines into the system. When ointment is rubbed into the skin, it is no doubt by means of the absor bent vessels that part of it is picked up and carried into the blood. The skin of some ani mals absorbs very readily, that of man not so readily. Still, experiment has shown that a person placed in a bath will absorb some water by the skin, and, if carefully weighed, he will be found heavier on leaving the bath than be fore entering it. Efforts have been made to nourish persons, who could not take food by the mouth, by means of milk baths, &c., though, from the comparatively small amount taken up, the success has not been great. Another method of administering medicines depends on the ab sorbing power of the skin and tissues beneath it, the method of hypodermic (Greek hupo, under, and derma, the skin). It consists in thrusting the point of a hollow needle under the skin. The needle is connected with a small syringe containing a drug in solution. When the piston of the syringe is pushed down, the fluid is forced along the hollow needle into the tissues under the skin, from which it is rapidly sucked up by the absorbent vessels and passed into the blood. Solutions of morphia are given in this way for the relief of pain.