By serum therapy we aim to introduce into the body, in the most effective manner, specific antibodies and to maintain a high concentration so long as necessary.
The results of investigations as to the influence of the place of introduction on the time when the maximum concentration of antibodies in the blood in passive immunization is reached may be summarized to this effect: On intravenous injection the maximum concentration is reached at once, while on subcutaneous, intramuscular and intraperitoneal injection it is reached only after an interval variously stated at from twenty-four to forty-eight or seventy-two hours. In man, Henderson Smith1 found absorption of diphtheria antitoxin from the subcutaneous tissue complete only after two or three days. In the case of certain agglutinins and of diphtheria antitoxin, the maximum concentration (according to Levin2) in the blood in animals is reached in about three days after subcutaneous and intramuscular
THE INTRAVENOUS INJECTION OF ANTITOXIC SERUM. JAMA. 1910;LIV(16):1312. doi:10.1001/jama.1910.02550420036003