SERUM ANTITETANICUM PURIFICATUM 465 



cresol, when either is used), and the total solids must not exceed 20 per 

 cent. Purified antitetanic serum must comply with the requirements for 

 loss of potency, control, labeling and standard for potency under Serum 

 Antitetanicum. 



2. BY INJECTION OF ANTIBACTERIAL SERUMS. Antibacterial, bac- 

 tericidal and bacteriolytic are three terms which are used in a loose, 

 interchangeable way, although they are not strictly synonymous. A bac- 

 tericidal serum is one which is able to kill bacteria; if at the same time 

 it dissolves the organism it is bacteriolytic. In either case the serum is 

 antibacterial. Bacteriolysis is the process in which bacteria are killed by 

 serums and may be either with or without solution; a bacteriolysis would, 

 then, be the substance in the serum which accomplishes the action. 



Opsonins are those substances existing in the serum which are capable 

 of rendering the bacteria susceptible to phagocytosis. Phagocytosis is the 

 process whereby the leucocytes take up bacteria, usually destroying them. 

 Those substances in opsonins which are thermostabile are called bacterio- 

 tropins or amboceptor and the thermo-labile part of opsonins is called 

 complement. 



Antibacterial serums are of two kinds. One, where organisms such as 

 typhoid, paratyphoid, colon and dysentery bacilli and the vibrio of cholera 

 are used as antigen, contains bacteriolysins, but the endotoxins released 

 during bacteriolysis are not neutralized. The other kind, with strepto- 

 coccus, staphylococcus and pneumococcus as antigen, contains endotoxins 

 and causes the formation of neither antitoxins nor bactericidal serums, 

 but does seem to stimulate phagocytosis. 



It is believed by some authorities that the antibacterial serums are 

 less efficacious than antitoxins because they are too specific; that is, they 

 contain only one strain of an organism. To correct this seeming defect 

 "polyvalent" serums are made. They are manufactured using several 

 strains of an organism as antigen. 



These serums are used principally in curative serotherapy and will be 

 discussed under that heading. 



C. MIXED ACTIVE AND PASSIVE IMMUNIZATION 



This consists in the simultaneous injection of the organism (either 

 killed or living) with its homologous immune serum. 



The immune serum gives the patient immediate, temporary immunity; 

 meanwhile, the organisms injected cause the tissues to build -up a com- 

 paratively permanent, active resistance. 



Serobacterins are bacterial vaccines that have been treated with an 

 immune serum for a time, then the serum removed, the bacteria washed 

 and suspended in isotomic saline solution. This "sensitization"' of the 

 bacteria is undoubtedly due to the union of the amboceptor of the immune 

 serum with the bacteria and yields quick immunity, as it does away with 



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