4S 
Series of dry 2 joints containing various amounts of mixed culture of tetanus, prepared 
June 2. 
Amount of 
tetanus 
culture. 
- 
Inoculated into 
mice. 
Result. 
c. c. 
0. 001 
June 17 
Remained negative. 
June 27 
Do. 
.0004 
June 17 
Do. 
June 27 
Do. 
.0002 
June 17 
Do. 
June 27 
Do. 
. 00012 
June 17 
Do. 
June 27 
Do. 
Compare this table with the control experiments on page 28 and we 
see the striking attenuating elf ect of exposure of tetanus on dry points. 
For instance: On Ma^^ 28 two tests of the control culture killed 
mice with typical s}m:ptoms of tetanus; whereas, on June IT, after an 
exposure of two weeks on dry points, doses of tetanus which repre- 
sented as much as fifty times the control doses had been rendered 
nontoxic for mice. It now remained to determine whether the tetanus 
on the point was dead or only attenuated. It was found after grow- 
ing a point of each series in 1 c. c. of bouillon for one week that the 
growth showed end-spore bearing organisms in microscopic prepara- 
tions and produced typical symptoms of tetanus when inoculated into 
mice. 
Again, on October d, four months after the dry points were pre- 
pared, specimens from series O.OOOd. 0.0002,. and 0.00012 c. c. were 
planted into bouillon and grown anaerobically. The culture again 
contained end spore bearing organisms which, inoculated into mice, 
produced F^pical symptoms of tetanus. The tetanus spores on the 
points were therefore not dead, although they had lost their viru- 
lence for mice VvFen inoculated directly. 
SUMMARY AND CONCLUSIONS. 
We examined the vaccines of 10 difierent manufacturers during a 
period of more than a year. 
All the samples examined were purchased on the open market, care 
being taken to biyv unbroken original packages from reliable pharma- 
cists who keep the product under proper conditions of light and tem- 
perature. With a few exceptions, the vaccine was examined before 
the time limit expired, if the time was given by the manufacturer. 
Of 190 dry points examined we found an average of 1,351 bacteria 
per point. A number of these points contained over 15,000 and one 
as high as 11,000 organisms. 
