Besides the above, there are also certain conditions connected with the action of poisons: (1) The poison is absorbed and distributed by the blood. (2) A portion is eliminated by the fluid secretions and excretions. (3) Another portion is for a time deposited in the tissues and organs of the body. These processes are of necessity simultaneous. The channels of entrance and exit are as follows: Of entrance we have--(1) _The blood-vessels as a result of wounds_--more important in a physiological than a medico-legal question. (2) _The skin and cellular membrane._--Absorption by the skin is modified by the condition of the part, and also by the form in which the drug is applied. Thus the skin of the arm-pits and groins is more absorbent than the palms of the hands. Watery solutions are not so effective as oily preparations, and the application of the drug in fine powder is more effectual than a watery solution of it. This is explained by the presence of a natural oily, unctuous substance on the skin, which prevents the direct contact of the watery solution, but if the solution be allowed to evaporate on the part, the substance thus left in minute division is then readily absorbed. The danger of allowing strong solutions of corrosive sublimate to evaporate on the head in the treatment of certain skin eruptions is thus explained. (3) _The lungs and air-passages._--Absorption by these organs is most active, hence the intense rapidity in the action of aerial poisons. (4) _The stomach and intestines._--Poisons introduced into the stomach or intestines take longer to arrive at the special organs on which they act than by the other channels of entrance. They are absorbed by the capillaries into the mesenteric veins, and before passing to the heart, by which they enter the general circulation, they pass through the liver, where they are in part excreted in the bile or deposited in the gland. The absorbing power of the stomach is modified by its fulness or emptiness, and poisons not soluble in water may be rendered so by the gastric secretion. The avenue of entrance may materially modify the action, and some poisons which act rapidly when entering by a wound, are inert when taken into the stomach. Snake poisons when given by the mouth are entirely harmless. Hydrogen sulphide is more toxic when inhaled than when taken in solution. This, though true in some cases, does not always occur; and the inertness of these poisons, it has been suggested, may be due to the elimination of them being as rapid as their absorption, so that a poisonous dose never enters the circulation. The intestines absorb more rapidly than the stomach, and this must be borne in mind when administering powerful drugs _per anum_. Of the channels of exit we have: (1) _The kidneys._ (2) _The lungs._ (3) _The bile._ (4) _The milk._ (5) _The saliva._ (6) _Mucous membrane._ (7) _The skin._