44 
North Carolina Experiment Station 
Table IV —Continued 
Flock Number 
Loss Before 
Vaccination 
Loss After 
Vaccination 
Total Loss 
Flock 
Total 
Loss 
Per 
Cent 
Loss 
Flock 
Total 
Loss 
Per 
Cent 
Loss 
Flock 
Total 
Loss 
Per 
Cent 
Loss 
39_ 
89 
15 
18 
75 
11 
15 
89 
26 
29 
40_ 
49 
35 
72 
15 
1 
7 
49 
36 
73 
41 
70 
35 
50 
70 
35 
50 
42 
87 
75 
87 
87 
75 
87 
43_ 
65 
30 
46 
35 
6 
17 
65 
36 
55 
44_ 
31 
20 
84 
5 
1 
10 
31 
27 
87 
45_ 
42 
7 
17 
35 
1 
3 
42 
8 
19 
46_ 
30 
13 
43 
17 
1 
6 
30 
14 
47 
47_ 
72 
12 
17 
60 
1 
1 
72 
13 
20 
48 
50 
35 
70 
50 
35 
70 
49 
18 
15 
83 
18 
15 
83 
25 
25 
100 
25 
25 
100 
51_ 
117 
31 
26 
86 
21 
24 
117 
52 
44 
52_ 
49 
15 
31 
34 
5 
15 
49 
20 
41 
53_ 
53 
8 
15 
45 
3 
7 
53 
11 
21 
54.__ 
47 
9 
19 
38 
0 
0 
47 
9 
19 
55_ 
61 
40 
66 
21 
2 
10 
61 
42 
64 
56_ 
33 
8 
24 
25 
0 
0 
33 
8 
24 
In estimating the flock mortality from this disease in France, d’Herelle 
(4) places the percentage from 40 to 70. 
The spread of infection through the flock after the initial inception is 
probably very rapid. This spread is accentuated by the fact that the birds 
dwell in close contact; eat and drink from common containers; range on the 
same ground, and are prone to pick the carcasses of birds dying from the 
disease. The more important factors of dissemination of this and other avian 
diseases in the flock are: 
Soil.—The dejecta from birds suffering from avian typhoid contains 
large numbers of virulent organisms expelled from the intestines with the 
fecal matter. It is the opinion of most investigators that the picking up of 
the organism from infected soil is the most common manner of the dissemi¬ 
nation of typhoid within the flock. 
After depositing the germ in the soil through the medium of the feces, the 
question arises as to the length of time which the organism will live and 
retain its vitality. It is evident that this period of time is not constant, and 
is governed somewhat by local conditions, and the virulence of the organism. 
d’Herelle (4) cites the following instance of an outbreak of avian typhoid 
from infected ground: 
“In several tests, it has been shown that an isolated infected chicken yard, 
cleaned and left unoccupied for 6 to 8 months, still contains virulent germs, 
for when repopulated with chickens from a region free of the disease, the 
infection breaks out again within a few days among the new occupants.” 
In the course of investigation of field outbreaks, this department secured 
the following interesting history, which would substantiate the statement 
that E. sanguinaria might retain its virulence in the soil for the period of a 
year: 
Avian typhoid had occurred at periodic intervals at this specific farm for 
five years, the owner selling the place and buying another. The new owner 
