THE BACILLUS OF TETANUS. 395 
and pericardial cavities as well as the blood of tetanic 
animals would cause tetanus when transferred to other 
animals. Kahlmeyer, Bruschettini, and others have 
obtained similar results. The toxin has also been 
demonstrated in the urine when large amounts have 
been inoculated. 
Courmont and Doyon believe that the so-called toxin 
elaborated by the tetanus bacillus is not the true poison, 
but is a ferment which forms from the poison in the 
body at the expense of the organism, and is found 
in the blood, sometimes in the urine, and in especial 
abundance in tetanized muscles. The action of tetanus 
toxin is never suddenly produced, though when once 
formed its absorption is rapid, but always requires a 
certain period of incubation. These authors hold that 
the substances produced by the tetanus bacillus must 
undergo a chemical change in the body, because after 
it is formed in the tissues it can be extracted from 
them by boiling, and when injected into other animals _ 
causes immediate tetanic symptoms without any period 
of incubation. But other observers repeating these 
experiments have failed to confirm Courmont and 
Doyon’s results, and appear to have proved their 
theory to be untenable. 
Tetanus Antitoxin. Behring and Kitasato were the 
first to show the possibility of immunizing animals 
against tetanus infection. Here the question of immu- 
nity against infection does not consist in producing an 
increased power of resistance against the development 
of the infecting agent, as is the case in most infectious 
diseases, but similar to diphtheria, in bringing about 
an immunity to the effects of the tetanus toxin. The 
bacillus of tetanus, as we have seen, does not belong 
