These are - (1) The transfusion of blood; and (2) the administration of saline solution (by intravenous infusion, by hypo-dermoclysis, or by rectal injection).

Transfusion is the transmission of blood from a vessel of one person to the vein or artery of another. The blood of the donor and the recipient tested together must show neither hemolysis nor agglutination, and the donor must be without transmissible disease, such as syphilis. 15

The direct method of attaching artery of donor to vein of recipient has been superseded by the simpler and easier indirect methods. The first of these to obtain wide recognition was the syringe-cannula method of Lindemann, in which a number of 20 c.c. syringes are employed and a special telescopic cannula for the vein. It permits the transference of 1000 c.c. in about ten minutes. The Unger method requires but one syringe.

A simpler method still is the use of an anticoagulant, the blood being drawn into a sodium citrate solution in such proportion that it contains 0.2 per cent. of sodium citrate, the method of Lewisohn and others; or into a vessel wetted with a solution of hirudin, the method of Satterlee and Hooker.

These methods permit accurate measurement of the blood transferred, and frequent repetition of the process. It is furthermore a simple matter to introduce saline into the donor's blood to replace the blood removed. With the anticoagulants all the apparatus necessary is a mixing vessel, a vein needle, and a funnel or fountain syringe with connecting rubber tube.

Transfusion of blood has advantages over saline infusion, for the new blood supplies nutritive material, oxyhemoglobin, and perhaps antibodies or antitoxins. Moreover, blood is not so quickly transuded out or excreted as a salt solution would be; consequently it tends to maintain the increased arterial pressure for a longer time. In hemorrhage transfusion may result in increased coagulability of the blood.

Levin has made a comparative study of the ability of saline solutions and transfused blood to replace blood lost by hemorrhage. In a number of dogs he let out enough blood to kill, i. e., about 4.5 to 5.5 per cent. of the body weight, and allowed the heart to come to a standstill. On replacing the blood with saline the heart began to beat again for a time, but the animal did not revive. On replacing the lost blood with fresh blood by transfusion, the heart began to beat again, and usually in as little as five minutes this resulted in the dog's return to just as good condition as before the experiment.

Therapeutics

1. Collapse or shock from any cause, but especially when there is hemorrhage. In the acute hemorrhages the safest guide is the blood-pressure, a pressure down to 70 indicating transfusion (Bernheim).

2. Profound anemia of any type. In the chronic bleedings and anemias the guide is the hemoglobin, transfusion being indicated at 40 per cent. if the hemoglobin is progressing downward (Bernheim).

In many cases of shock, hemorrhage, or profound anemia a preliminary transfusion may permit necessary surgery. In pernicious anemia, for example, it is the practice to transfuse both before and after splenectomy.

3. Hemophilia, especially before an operation, or in the presence of hemorrhage. In several cases Lindemann reports persistence of increased coagulability for many months.

4. Profound malnutrition and the psychoses of inanition.

5. Protracted weakness or prostration.

6. In infectious conditions, such as malignant endocarditis or any form of sepsis, the blood of an immune donor, i. e., one who has had such an infection and recovered, or one treated by vaccines made from the germ involved, has been tried, in a few cases with seemingly good results. It has failed to help in typhoid fever.

(Defibrinated blood was formerly employed in some instances, but the process of defibrination introduces possibilities of infection and is decidedly disadvantageous.)

Saline Infusion

Intravenous infusion requires a graduated reservoir for the saline, a rubber tube for transmission of the liquid, and a cannula or nozzle (the glass portion of an eye-dropper or a vein-needle will do) for insertion into the vein. The amount administered is from 500 to 1500 c.c. (about 1 to 3 pints), quantities much above this being contraindicated, as noted below.

The solutions employed for infusion are:

1. Normal saline (liquor sodii chloridi physiologicus) which contains 0.85 per cent. of sodium chloride, about a full teaspoon to one pint (for frogs normal saline is of 0.7 per cent. strength). This is the most universally employed infusion fluid; but, because of the absence of all other salts, especially those of potassium and calcium, which are required by the tissues and, according to Jacques Loeb, prevent sodium chloride poisoning, and because its reaction is not alkaline, it is not by any means the best solution. Indeed, normal saline is better made from hard drinking-water, which contains calcium, than from distilled water. For pure sodium chloride intravenously is poisonous, and normal saline made from distilled water may have a veratrine action upon muscle, i. e., it may cause increased contraction with retarded relaxation; while if the slightest amount of calcium salt is present, the chance of this action is avoided. Ordinary table salt regularly contains some calcium. The 0.7 per cent. saline is not to be employed, for in some hemolytic conditions the blood has been found to hemolyze with this strength saline.

2. Dawson's solution - 0.8 per cent. of sodium chloride with 0.5 per cent. of sodium bicarbonate.

3. Locke's solution - the best of all. Its formula is: Sodium chloride, 0.9 gm.; potassium chloride, 0.042 gm.; calcium chloride, 0.0024 gm.; sodium bicarbonate, 0.03 gm.; dextrose, 0.1 gm.; and distilled water, a sufficient quantity to make 100 c.c. This contains the necessary salts, and is alkaline and nutritive.

4. The Ringer-Locke solution - Locke's, with the dextrose omitted.

5. Ringer's solution, much used in the laboratory, contains the chloride of sodium, 0.7 per cent., with the chlorides of potassium and calcium. It was especially designed for frogs and turtles.