144 
II . — Summary of controls. 
Result. 
Contact of culture in the feces. 
Normal 
feces. 
Total. 
Short. 
24 hours. 
48 hours. 
72 hours. 
Total 
63 
36 
2 
2 
3 
106 
Positive 
52 
28 
2 
0 
0 
82 
Negative 
11 
8 
0 
2 
3 
24 
Percent positive 
84 
78 
100 
0 
0 
a 80 
® Specimens containing no typhoid culture and those having culture added 48 and 72 hours before ex- 
amination not counted in calculating this percentage. 
III.— Persons furnishing two or more specimens. 
C. H. J 8, -f; 27A, and 1013, — . 
G.M 31, 239, +; 1003, -. 
W. S 57 and 79, — . 
A. S 58 and 80, — . 
T. S 59 and 81, — . 
A.C 274, 381, and 611, -. 
W.C 275, +; 303, +; 463, -. 
J. C 276, 396, and 616, -. 
T.C 412 and 737, -. 
E. J 280, +; 372, 945, -. 
R.B 304 and 1040, -. 
T. B 305 and 1038, -. 
M.B 405, +; 1039, -. 
C.B 309, 1037, +. 
B 306 and 1036, -. 
C. E 479, +; 687, 1021, -. 
L. K 1014 and 1020, 1026 and 1027, -. 
L. K 1005 and 1010, 1028 and 1029, -. 
I. K 1016 and 1018, 1034, -. 
D. K 1004 and 1009, 1030 and 1031, -. 
R.K 1011 and 1017, -. 
M. K 799, 1015, 1019, 1024, and 1025, -. 
A. K 838, 1007, 1032, and 1033, -. 
J. K 797, +; 908, 1006, 1012, 1022, and 1023, - 
IV. — Bacteriologists. — Rosenau=Il; Lumsden=L; Miller=M; Hart=H; Cannon=C. 
These initials appear in the table under the column “ examiner.” 
The laboratory work referred to in the above tables was controlled 
by two methods. The first, followed only for about one week, was 
to submit to the examiners at the same time that the collected 
specimens were dehvered specimens of known normal feces. To some 
of these control specimens 5 drops of a 24-hour broth culture of B. 
typhosus were added an hour or two before the examination was 
begun. To others no typhoid culture was added. The examiners 
were not told which of the control specimens contained typhoid 
culture until after their report on the results of the examinations 
was made. The control specimens, however, were kept separate from 
the collected specimens. 
By this method of three control specimens containing no typhoid 
culture all were reported negative. Of 7 control specimens contain- 
ing typhoid culture, 4 were reported positive and 3 negative. The 
