TYPHOID BACILLUS 371 
distributed in flasks, 25 cc. to a flask. The ox-bile prevents the 
coagulation of the blood. Three cc. of blood, according to the Cole- 
man technique, 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 cc. of blood will not give 
a growth of typhoid bacilli, whereas 10 cc. or, better, 15 cc. 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 possibihty 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 proper- 
ties; occasionally, however, a strain is met with which will not agglu- 
tinate with specific typhoid serum even after long-continued transfer 
on artificial media. ^Iclntosh and McQueen^ 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 agglutinins 
apparently as readily as the agglutinating strains. Arkwright^ 
immunized rabbits against the two types of typhoid bacilli, S. and R., 
into which typhoid cultures occasionally dissociate, and found that each 
type was agglutinated by its homologous serum; but each serum was 
nearly devoid of agglutinating power for the opposite strain. Gay 
and Claypole^ 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 diagnosis 
of typhoid fever beyond question of doubt. 
The isolation of typhoid bacilli from rose spots is performed in 
essentially 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 glucose broth or in the bile medium. NeufekH 
and Richardson'^ have successfully isolated typhoid bacilli from the 
roseola of typhoid fever is a considerable number of cases. Thus, 
Xeufeld*^ obtained cultures in 1.3 of 14 cases examined, and Richardson 
1 Jour. Hyg., 1914, 13, 409. - Jour. Pathol, and Bacteriol., 1921, 24, .36. 
3 ,Jour. Am. Med. Assn., 1913, 60, 1141; Arch. Int. Med., 1913, 12, 613. 
4 Ztschr. f. Hyg., 1899, 30, 498. = Philadelphia Med. Jour., March 3, 1900. 
« Loc. cit. 
