 It was noted that administering drugs intravenously strengthened their effect, and—since such drugs as heroin and cocaine were already being used to treat a wide variety of ailments—many patients were given injections of "hard" drugs for such ailments as alcoholism and depression.The hypodermic needle and syringe in its current form was invented by the French scientist Charles Pravaz in 1851, and became especially known during the wars of that and the subsequent decade.However, the first well-known attempt to inject drugs into the body was a 1667 attempt to inject a solution of opium into a dog, and some had suspected that parenteral administration of drugs may work better based on the practise of rubbing opium and other drugs into sores or cuts on the skin for the purpose of causing systemic absorption and the beginnings of scientific understanding of the functioning of the lungs.