The vaccines, viruses and serums constitute one of the most important groups of drugs with which the physician has to deal. Some preparations of this group are specific cures for certain diseases; others are invaluable in prophylaxis and diagnosis. The supervision of these drugs is in charge of the United States Public Health Service, which periodically makes inspections of laboratories licensed in accordance with the law passed by Congress in 1902. Anti-diphtheric and antitetanic serums are required to conform strictly to the standards which have been established by the United States Public Health Service. There being no established standard for the various other products, they are not examined for their therapeutic value in the laboratory but are tested for the amount of preservative and freedom from bacterial and toxic contaminations. The preparations of this class most widely used are the following, which will be found in their respective alphabetical positions in this book:

Antidiphtheric Serum, under Serum Antidiphthericum.

Antitetanic Serum, under Serum Antitetanicum.

Bacterial Vaccines, under Vaccine.

Tuberculin, under Tuberculinum.

Vaccine Virus, under Virus Vaccinum.