2. Epidermic (Epidermatic)

Epidermic (Epidermatic). Here medicines are incorporated in wool fat, or other fats, and rubbed with friction directly upon the skin, thus promoting their passage through and between epidermal cells; best to apply where skin is thinnest (axillae, groins, abdomen, insides of thighs) in the form of ointments, oleates, or oils. This method also is called inunction.

3. Enepidermic (Enepidermatic)

Enepidermic (Enepidermatic). Here medicines are applied to the skin without friction; chloroformic and oleic acid solutions of the alkaloids (aconitine, atropine, morphine, strychnine) pass by osmosis most easily; solutions in a mixture of chloroform and alcohol nearly as fast; aqueous solutions slower, while pure alcohol causes an outward osmotic flow. In this way medicinal effect is secured through plasters and poultices.

4. Endermic. (Endermatic). - Here we first produce a blister on the skin by the use of strong ammonia water (saturated cloths) or cantharides (cerate, collodion), then remove with scissors the epidermis, and apply upon the denuded surface (derma) the powdered medicine - morphine, atropine, quinine, strychnine, etc.; at present little employed.

3. By Rectum

By Rectum. This is accomplished by enemas or suppositories, being suited best to disagreeable tasting alkaloids, acid solutions, etc. While absorption is usually twice as slow by this method as by the stomach, yet salts of atropine and morphine in solution enter circulation just as quickly, while those of strychnine more quickly than even by the mouth.

4. By Lungs: Respiration. - Vapors of liquids or solids are inhaled with the air, thereby bringing the system quickly under the drug's influence; this quick action is due to the rapid absorption, owing to the extensive surface (lungs, etc.) to which applied, and to the fact that volatile substances penetrate the tissues most readily. Some vaporize at all ordinary temperatures, others at that of the body, while many have to be heated. 'Most anaesthetics act by this method.

5. By Arteries: Arterial Transfusion. - Large quantities of fluid (defibrinated human or lamb's blood - ℥iv-8; 120-240 Ml. (Cc.), etc.) may be introduced into circulation, through the radial or posterior tibial, by the transfusion syringe. This is safer than by the veins, owing to the less likelihood of admitting air (causing fatal syncope) or of producing thrombosis, as the injected solution has to traverse the capillaries prior to reaching the right side of the heart, thus avoiding any likely sudden distention.

6. By Veins: Intravenous Injection. - This is the most perilous of all methods, being resorted to only in extreme emergencies to save life; thus blood or milk in hemorrhage, epilepsy, uraemia, cholera-collapse; saline solutions in cholera-collapse, diabetic coma; diluted ammonia water, ether, brandy or whisky in bites of reptiles, venomous insects, hydrocyanic-acid poisoning, opium-narcosis, chloroform-asphyxia. It is better here to inject into a vein of the leg than of the arm, so that the drug may be less concentrated when it reaches the heart, thereby avoiding possibly any cardiac depression.

7. By External Application

By External Application. Many powdered medicines when dusted on abraded surfaces, or applied by insufflation to the nares, fauces, larynx, become absorbed gradually, and affect the system locally and generally; this equally applies to drops and washes when introduced into the eyes and ears, also to atomized vapors, sprays, etc. The method known as cataphoresis consists of producing osmosis, through the skin or mucous membrane, from one point to another, of medicines by the galvanic current, the positive pole being medicated and placed over the affected part, the negative slightly remote; this is a mechanical action, and is accomplished by covering the seat of pain with a paper, linen, or gelatinous disk moistened with a solution of the drug, and placing thereon the anode, or may apply direct the sponge electrode saturated with the medicine; this method affects only tissues between the poles, and solutions of aconite, chloroform, cocaine, and morphine yield good results.