A fluid separated from the coagulated blood of a horse, immunized by inoculation with diphtheria toxin. It is a yellowish-brown powder, odorless, and slightly transparent. It loses strength, and the date of its manufacture should be known, also its strength, the name of the preservative, and the date beyond which it will not retain its strength. The standard must be that approved by the United States Public Health service. It must have a potency of not less than 250 antitoxic units per mil.

Average dose, hypodermic, 10,000 units.

Average dose, protective, 1000 units.

The U. S. P. also recognizes the Purified Antidiph-theric Serum, Diphtheric Antitoxin Globulins, a solution in physiological solution of sodium chloride, of certain antitoxic substances obtained from the blood serum or plasma of the horse or other large domestic animal which has been properly immunized against diphtheria toxin; and the Serum Antidiphthericum Siccum, Dried Diphtheria Antitoxin, which must be hermetically sealed. The average dose of each is the same as of diphtheria antitoxin. (See p. 283.)

Virus Vaccinicum, Vaccine Virus, Glycerinated Vaccine Virus, Smallpox Or Jennerian Vaccine

The pustules of vaccinia or cowpox from healthy vaccinated cows or calves. (See p. 285.)