508 Typhoid Fever 



reaction for thirty-three days after birth. J. P. C. Griffith,* Barber, f 

 Pepper and Stengel,! and others have seen similar cases. Charrier 

 and Apert examined an embryo aborted by a mother in the third 

 week of typhoid fever, in which there was a total absence of any agglu- 

 tinating property in the blood of the fetus, though it was present in 

 the blood of the placenta. 



The specific nature of the reaction is now universally accepted. 

 Normal human serum, when concentrated, occasionally exerts a slight 

 agglutinating effect upon the typhoid bacillus, but this seldom occurs 

 except with concentrations exceeding those employed for diagnostic 

 purposes. 



The blood of certain animals normally possesses an agglutinating 

 property for the typhoid and other bacilli. Some individuals are 

 peculiar in that their blood acts more strongly in its agglutinating 

 and bacteriolytic action than others. 



The blood in a few diseases that may or may not be related to typhoid 

 (paratyphoid) occasionally produces a reactive effect upon the typhoid 

 bacillus. The number of cases in which such errors can occur is very 

 small, and the validity of the test is very slightly influenced by them. 



Fritz Kohler || found that the blood in chlorosis occasionally gave 

 the agglutinative phenomenon with the typhoid bacillus, and that in 

 icterus the blood was very apt to do so. In dogs whose common bile- 

 ducts were ligated so that icterus developed, the blood nearly always 

 developed it. The agglutinating substance in icterus is thought to be 

 taurocholic acid. 



Villiez and Battle ** found a positive reaction in a case of malaria 

 from Madagascar. 



The reactive phenomena are very slightly interchangeable for 

 species of bacteria intermediate between the typhoid and colon bacilli. 

 Far from lessening the value of the test, this, as Welch points out, 

 only argues for the close relationship of the species acted upon. 



The typical reaction does not occur with allied members of the 

 typhoid group of bacilli. Attempts to make the colon bacillus ag- 

 glutinate by the application of typhoid serum fail. In suspected 

 typhoid, in which the reaction upon the colon bacillus takes place, 

 it is impossible to eliminate the possibility of combined typhoid and 

 colon bacillus infection, as suggested by Johnston and McTaggart, and 

 the paratyphoid bacillus and paratyphoid fever must not be forgotten. 



Widal and Courmont found that all human serums, whether normal 

 or typhoid, have a slight action upon the colon bacillus in dilutions of 

 1:10, whereas normal serum, as a rule, has no effect upon the typhoid 

 bacillus in this dilution. This may indicate that the constant presence 

 of the colon bacillus in the alimentary canal may occasion the presence 

 of some immune substance in presumably normal blood. 



The Technic of WidaPs Reaction. Widal ft first suggested that, 

 to make the test, a small quantity of blood be withdrawn in a sterile 

 syringe from the median cephalic vein, and a few drops of it be added 

 to a fresh bouillon culture of the typhoid bacillus in the proportion 



* See "Amer. Jour. Med. Sci.," N. S., Jan.-June, 1897, vol. cxm, 

 p. 621. 



f "New York Med. Jour.," April 16, 1898, vol. LXVII, No. 16. 



% "Year-book of Medicine," 1897. 



" Compte-rendu de la Soc. de Biol. de Paris," Jan. 1, 1897. 



|| "Centralbl. f. Bakt. u. Parasitenk.," May 22, 1901, xxix, No. 

 17, p. 683. 



**"La Presse med.," 1896, No. 84. 



ft "La Semaine medicale," 1896, p. 259. 



