The best place to inject is under the skin of the back or chest. The forearm is usually selected, but there are many objections to it. If the injection is made into the leg or arm, the point of the needle should be directed towards the body.
1. Surgical cleanliness must be observed. The hands of the operator and the skin of the patient at the spot chosen for injection must be properly cleaned with an antiseptic lotion, e.g., chinosol (1 in 1000) or carbolic acid (1 in 60). The site of injection may, as an alternative, be painted with iodine which, indeed, is the preferable method.
2. The hypodermic syringe and needle must be perfectly cleaned; if possible they should be boiled, or an antiseptic lotion, or alcohol (brandy or whisky) may be syringed through them.
3. The solution to be injected should be made in a clean, i.e., boiled, spoon, by adding the drug to boiled water.
4. Draw solution into the syringe, hold the syringe with the needle end pointing upwards, so as to allow any air to rise above the fluid, and push the piston up till all air has been driven out and the solution begins to come through the needle.
5. Pinch up the skin where the injection is to be made, push the needle well through and then under it, keeping the point slightly away from the skin until the needle is almost entirely covered. The point of the needle will now lie in the loose tissue—between the skin and the muscle—into which the fluid is to be injected.
6. Holding the needle firmly, slowly press the piston until the required amount has been injected; withdraw the needle slowly, keep the finger over the minute opening in the skin, so as to close it at once, and with another finger rub for a few seconds, where the fluid has been injected, in a direction away from the opening, to assist its absorption.
After giving an injection, wash out the syringe as before, dry needle well, and pass a piece of thin wire through it to keep it open. The needles are sent out with wire in them to keep the fine channel open; of course the wire must be removed before the needle is put on to the syringe.
As strong solutions of permanganate of potash attack the plunger of the piston, when this drug has been injected, the syringe should be well washed with water directly after its use.
Hypodermic tablets.—Solutions for injection are best made from tablets which are specially prepared for the purpose. A hypodermic tablet should be dissolved in about ten drops of hot water, but as each contains a definite amount of the drug, it does not matter in exactly how much water the dose is dissolved. In injecting certain preparations of quinine, which are not easily soluble, so much water may be required that two or three separate injections are necessary; there is no objection to this, the important thing is to have the quinine really dissolved.