44 
offer a more favorable medium for preserving the vitalit}- of the 
tetanus spores. 
The sterile ivory points were prepared in the usual manner with 
the vaccinal serum but contaminated with definite measured amounts 
of tetanus culture. 
Each point of the first series contained 0.00012 c. c. of pure bouillon 
culture of tetanus; each point of the second series contained 0.0002 
c. c. of pure bouillon culture of tetanus; each point of the third series 
contained 0.0004 c. c. of pure bouillon culture of tetanus; each point 
of the fourth series contained 0.001 c. c. of pure bouillon culture of 
tetanus. 
These were allowed to diw in the usual manner and kept in the cool 
chamber at 20°-22° C., well protected from the light. These points 
were tested at intervals on mice and in cultures as shown in the 
following tables: 
Dry points containing vaccine serum lymph’^) ivere contaminated with 0.00012 c. c. of 
tetanus culture and kept at 22° C. in the dark. From time to time they were tested, ivith 
the following result: 
Date pre- 
pared. 
Inocu- 
lated 
into 
mice. 
Num- 
ber 
of 
days. 
Symptoms. 
Result. 
1st 
day. 
2d 
day. 
3d 
day. 
4th 
day. 
5th 
day. 
6th 7th 
day. day. 
8th 
day. 
9th 
day. 
10th 
day. 
Mar. 12 
Do 
May 28 
June 17 
June 27 
77 
107 
117 
N 
N 
N 
Negative. 
Do. 
Do. 
Do 
! . 
It will be seen that a quantity of tetanus spores equal to five times 
the minimal lethal dose lost its toxicity for mice within seventy-seven 
days. The spores, however, were not dead, for these points planted 
in bouillon and grown anaerobically in a Nov}^ jar for one week gave a 
culture rich in end spore-bearing rods, which caused typical tetanus in 
a mouse in doses of 0.001 c. c. 
Dry points containing vaccine serum {^'lymph^’) ivere contaminated, with 0.0002 c. c. of 
tetanus culture and kept at 22° C. in the dark. From time to time they were tested, with 
thefollowi ng result: 
Date pre- 
pared. 
Inocu- 
lated 
into 
mice. 
Num- 
ber 
of 
days. 
SjTuptoms. 
Result. 
1st 
day. 
2d 
day. 
3d 
day. 
4th 
day. 
5th 
day. 
6th 
daj'. 
7th 
day. 
8th 
day. 
9th 
day. 
10th 
day. 
Mar. 12 . . 
Do 
May 28 . 
June 17. 
June 27 . 
/ / 
107 
117 
N 
N 
N 
Negative. 
Do.' 
Do. I 
Do 
These points, containing approximately ten times the minimal fatal 
dose of tetanus, apparenth" soon lost their virulence when inoculated 
