THE CONTROL OF TYPHOID FEVER BY VACCINATION. 



By MAZYCK p. RAVENEL, M.D. 



(Read April iS, 19 13.) 



The discovery of the prevention of disease by the use of atten- 

 uated cultures of bacteria is due to Pasteur, who, in 1879, discov- 

 ered that when a chicken was inoculated with a weakened culture of 

 the chicken cholera bacillus it became sick but soon recovered and 

 thereafter could resist injections with the virulent germ without 

 injury. Following Pasteur's suggestion, those methods by which 

 we protect against disease through the use of attenuated cultures 

 are spoken of as "vaccination," and the materials "vaccines," in 

 honor of Sir Edward Jenner, who discovered vaccination against 

 small-pox. Pasteur's later success in immunizing animals against 

 anthrax by similar methods led to experiments on laboratory animals 

 looking toward immunization against typhoid fever. 



In 1896, Doctor (now Sir) Almroth E. Wright inoculated two 

 men with killed cultures of the typhoid germ. Pfeiffer and Kolle 

 in the same year immunized two men and made a subsequent study 

 of the changes produced in the blood. In 1897, Dr. Wright pub- 

 lished the results of his inoculations made on eighteen men, which 

 convinced him that the method was a practical one in the prevention 

 of the disease. Dr. Wright soon after tried it in the British army 

 in India, but the outbreak of the Boer War gave him his first oppor- 

 tunity to carry it out on a large scale. The results were hard to 

 collect accurately and opinions dififered greatly as to the ultimate 

 success of the method. Dr. Wright, however, believed that the inci- 

 dence of the disease was diminished about one half, and that the 

 mortality was favorably influenced to even greater extent. 



We now understand some of the reasons for the varying effect 

 of the vaccine. At that time the cultures were heated to a tempera- 

 ture of 60° C. in order to destroy their vitahty. It has since been 



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