336 THE ALCALIGENESDYSENTERY^TYPHOID 



distributed in flasks, 25 c.c. to a flask. The ox bile prevents the 

 coagulation of the blood. Three c.c. of blood, according to the Cole- 

 man technic, are added to the flask of this medium, incubated for 

 eighteen to twenty-four hours, then plated out on agar. Experience 

 has shown that larger amounts of blood are more satisfactory, for 

 it has been found that not infrequently 5 c.c. of blood will not give 

 a growth of typhoid bacilli, whereas 10 c.c. or, better, 15 c.c. will give 

 a growth. The organisms obtained in pure culture are identified by 

 agglutination with a known specific typhoid serum of high potency. 

 Such a serum used in high dilution reduces the possibility of "group 

 agglutinins" which might otherwise give an erroneous diagnosis. 

 It must be remembered that occasional strains of typhoid bacilli are 

 isolated from the body which are typical culturally, but which are 

 non-agglutinable. Frequently a few successive transfers of these 

 organisms on artificial media will restore their agglutinating properties; 

 occasionally, however, a strain is met with which will not agglutinate 

 with specific typhoid serum even after long-continued transfer on 

 artificial media. Mclntosh and McQueen 1 have found that at least 

 certain strains of these non-agglutinable typhoid bacilli will stimulate 

 the production of typical typhoid agglutinins if they are injected into 

 animals. The agglutinins developed in these animals will promptly 

 clump agglutinable typhoid bacilli, but will not agglutinate the non- 

 agglutinable strains which incited the production of these agglutinins. 

 These non-agglutinable strains, however, will absorb the agglutimns 

 apparently as readily as the agglutinating strairs. Gay and Claypole 2 

 have found similarly that occasional strains of typhoid bacilli isolated 

 from "typhoid carrier" rabbits may be non-agglutinable. They 

 absorb agglutinin, however. They suggest the use of sera obtained 

 from animals immunized with cultures of typhoid bacilli grown upon 

 agar containing the blood of man. The isolation of typhoid bacilli 

 from the blood stream and their identification establishes the diag- 

 nosis of typhoid fever beyond question of doubt. 



The isolation of typhoid bacilli from rose spots is performed in essen- 

 tially the same manner, except that fluid is expressed from the rose 

 spot after the skin is sterilized over it, and the expressed fluid is grown 

 either in the dextrose broth or in the bile medium. Neufeld 3 and 

 Richardson 4 have successfully isolated typhoid bacilli from the roseola 



1 Jour. Hyg., 1914, xiii, 409. 



2 Jour. Am. Med. Assn., 1913, Ix, 1141; Arch. Int. Med., 1913, xii, 613. 

 'Ztschr. f. Hyg., 1899, xxx, 498. 



4 Philadelphia Med. Jour., March 3, 1900. 



