47 
Glycerinated virus {manufacturer Xo. B) contaminated ivith 0.00002 c. c. of a mixed culture 
of tetanus. 
This table shows that after August 28 the tubes failed to produce 
tetanus in the mice. Therefore, on September 30, we subjected the 
remaining two tubes to cultivation in bouillon for one week and found 
that in one of the tubes the tetanus was still alive, for the growth 
showed rods bearing end spores and produced typical tetanus in mice. 
In the other tubes there was no growth of tetanus. 
A comparison of these two tables shows that make No. B of glycer- 
inated virus required four months to attenuate the same amount of 
tetanus which make No. A attenuated in one month and killed completely 
in two months. This fact led to a study of the comparative effects 
of the different percentages of pure glycerin on the tetanus organism 
and its toxin. This study will be reported upon later. 
VIABILITY OF TETANUS IN MIXED CULTUEE ON DRY POINTS. 
The same mixed culture of tetanus used in the two preceding experi- 
ments was also used to contaminate dry points. The tips of the 
sterilized ivory points were dipped into vaccine serum freshly obtained 
from the calf. To each point was then immediately added a definite 
measured amount of the tetanus culture. The points were allowed to 
dry in the air and kept in a cool (20°-22^ C.), dark place until tested. 
To contaminate the first series 0.001 c. c. of the tetanus culture was 
used; 0.0004 c. c. of the tetanus culture was used to contaminate the 
second series; 0.0002 c. c. of the tetanus culture was used to contami- 
nate the third series; 0.00012 c. c. of the tetanus culture was used to* 
contaminate the fourth series. 
