5 58 Typhoid Fever 



careful in this particular as they should be, the disease 

 would be much less frequent in regions remote from the 

 filth and squalor of large cities with their unmanageable 

 slums, and the distribution of the bacilli to villages and 

 towns, by watercourses polluted in their infancy, might 

 be checked. 



Antityphoid Serums. Animals can be immunized to 

 this bacillus, and then, according to Chantemesse and 

 Widal, develop antitoxic blood capable of protecting other 

 animals. Stern * found in the blood of human convalescents 

 a substance thought to have a protective effect upon infected 

 guinea-pigs. His observation is in accordance with a pre- 

 vious one by Chantemesse and Widal, and has recently been 

 abundantly confirmed. 



The immunization of dogs and goats by the introduction 

 of increasing doses of virulent cultures has been achieved 

 by Pfeiffer and Kollef and by Loffler and Abel.J From 

 these animals immune serums were secured. 



The typhoid immune serum is specific, but its action 

 requires the presence of additional complementary sub- 

 stance, and by itself it is useless. Indeed, by itself it may 

 do harm by causing the formation of anti-immune bodies. 



So far, no serum has been produced that is of any value 

 in therapeutics. 



Widal Reaction of Agglutination. In 1896 Widal and 

 Gruiinbaum, working independently, discovered that when 

 blood -serum from typhoid fever patients is added to cul- 

 tures of the typhoid bacillus a definite reactive phenomenon 

 occurs identical with that already described by Charrin and 

 Roger and Gruber and Durham. The phenomenon, now 

 familiarly known as the "Widal reaction," consists of 

 complete loss of the motion so characteristic of the typhoid 

 bacillus, and collection of the micro-organisms into clusters 

 or groups agglutination. The bacteria frequently appear 

 shrunken and partly dissolved. 



The technic of the test is outlined in the section upon 

 Agglutination (q. v.). For the use of the practising physician, 

 commercial houses now furnish various outfits known as 



* "Zeitschrift fur Hygiene," 1894, xvi, p. 458. 



t "Centralbl. f. Bakt. u. Parasitenk.," Jan., 23, 1896.. Bd. xix, No. 

 23, P- 51- 



J Ibid., 1896. 



"La Semaine Medicale," 1896, p. 295. 



