SERUM THERAPY. 



The principles involved in serum therapy 

 may be considered under three heads namely 

 (a) Antitoxins, (b) Bacterial or antibacterial Inaccurate 

 serums (c) and Vaccination. The terms, ^" °* ''^*™^- 

 "anti-bacterial," "bactericidal" and "bacterio- 

 lytic" are frequently found to be used inter- 

 changeably. Strictly speaking this is inac- 

 curate, as in the true sense of the term they are 

 not synonymous. Bactericidal serums we, of 

 course, understand to mean those serums which 

 are able to destroy bacteria. If during the pro- 

 cess of destruction, they are able also to dis- 



solve bacteria, they are truly bacteriolytic. In "Bactericidal," 

 , . -, . ■ , T "Bacteriolytic" 



either event the serum is antibacterial, in and 



t)^hoid fever the serum kills but does not dis- "^^i^^^l^^^^" 

 solve the bacteria. In cholera the action of the 

 serum is both to kill and to dissolve the bacteria. 

 Until recent years the action of toxin and the 

 efficiency of an antitoxin could only be decided 

 upon by experiments on the living subject. 

 These experiments are still kept up, but not ex- 

 clusively, as the nature of the action of the anti- 

 toxin could not easily be determined by this 

 method alone. Since the introduction of test- 

 tube experiments into laboratory work, some Experiments, 

 of the difficulties which existed have been 

 removed. There are still differences of opinion 

 among authorities, as to whether antitoxin 

 combines chemically with toxin, or whether its Authorities 

 protecting (immunizing) power is due to it^ Not in Unison. 

 171 



