15 
\ 
4. The property of destroying the tetanus poison is absent in the blood of animals 
which have not been immunized against tetanus. If the tetanus poison be given to 
susceptible animals it may be demonstrated in. the blood and other body fluids after 
the death of the animal. 
For instance: A rabbit was immunized against tetanus to such a high degree of 
immunity that it was able to withstand 10 c. c. of a 'sdrulent culture containing the 
tetanus organism, 0.5 c. c. of which was sufflcient to kill a normal rabbit. This rabbit 
was not only able to withstand the infection of living tetanus bacilli, but was also 
immune to the tetanus poison. Thus it withstood without any symptoms twenty 
times the quantity of tetanus poison sufflcient to kill a normal rabbit. 
This rabbit was bled from the carotid, and before the blood clotted 0.2 c. c. was 
given to a mouse and 0.5 c. c. to another. After twenty-four hours both of these treated 
mice and two control mice were inoculated -with a virulent tetanus bacillus. The 
amount injected was so great that the control animals showed tetanus in twenty hours 
and were dead in thirty-six hours. Both treated mice, on the other hand, remained 
well. 
The larger quantity of blood was allowed to stand until the serum separated. Of this 
serum six mice were injected with 0.2 c. c. each into the peritoneal ca^uty. Twenty- 
four hours later they were infected and remained well, while the control mice died in 
less than forty-eight hours. 
It was further found that the serum had a therapeutic value in that the mice were 
first infected and afterwards protected by injecting the serum into the peritoneal 
ca^'ity. 
They firrther made experiments to demonstrate that the serum has an enormous 
power of destroying the poison. 
Of a tetanus cultirre ten days old which was freed from bacilli by filtration. 0.00005 
c. c. was sufflcient to kill a mouse in four to six days and 0.0001 c. c. was sufflcient 
to kill a mouse with certainty in two days. However, 5 c. c. of the serum from the 
tetanus immune rabbit was mixed with 1 c. c. of this culture, and the serum was 
allowed to act twenty-fonr hours upon the culture containing the tetanus poison. Of 
this mixture, foin mice were given each 0.2 c. c., containing 0.0033 c. c. of the cul- 
ture, or more than 300 times the dose otherwise fatal for mice. All four of the mice 
remained well. The control mice, on the other hand, died in thirty-six hours with 
0.0001 c. c. of the fluid. The mice which were treated as above described, as well as 
those which had received the mixture of tetanus poison with serum, so far as can be 
told, remained well. Later they were injected repeatedly with 'vii’ulent tetanus 
bacilli, which they withstood without a trace of symptoms. 
This fact is of very particular note, because in the innumerable experiments no 
mouse, no rabbit, in fact no animal so far tested has shown a natural immunity against 
tetanus. We therefore may draw the conclusion that the above-mentioned explana- 
tion of the conditions of immunity which may be obtained promptly and without 
difficulty, and which may be accomplished without harm to the animals in the process 
of immunization, will prove of far-reaching value. It is to be understood that control 
animals were tested with the blood and seriun of nonimmune rabbits. The same may 
be said to be true of cattle and sheep. 
We permit ourselves from our results to A^enture the conclusion that, after finding a 
therapeutically potent substance useful for animals, it Avill also be useful in the treat- 
ment of diphtheria and tetanus in man. We only desire to call attention to one thing 
in conclusion: In former times the transfusion of blood was considered to be a heroic, 
but in certain cases a very powerful, curatHe agent. In later times it was thought 
that physiological salt solution was able to accomplish the same result. On the other 
hand, our experience makes memorial the phrase “Blut ist ein ganz besonderer saft.” 
