390 BACTERIOLOGY. 
toxins, and tetanus did not develop; but if the wounds 
containing the foreign bodies became infected with 
other bacteria, tetanus developed and the animals died. 
From these experiments it seems that a mixed infection 
is necessary to the development of tetanus when the 
infection is produced by spores. 
This fact is of the greatest importance in natural 
tetanus. Here the infection may be considered as 
prubably invariably produced by the bacilli in their 
spore state, and the conditions favoring infection are 
almost always present. A wound of some kind has 
occurred, penetrating at least through the skin, though 
perhaps of a most trivial character, such as might be 
caused by a dirty splinter of wood, and the bacilli or 
their spores are thus introduced from the soil in which 
they are so widely distributed. If in any given case, 
the tissues being healthy, the ordinary saprophytic 
germs are killed by proper disinfection at once, a 
mixed infection does not take place, and tetanus will 
not develop. If, however, the tissues infected be 
badly bruised or lacerated, the spores may develop 
and produce the disease. With regard to the persist- 
ence of tetanus spores upon objects where they have 
found a resting-place, Henrijean reports that by means 
of a splinter of wood which had once caused tetanus 
he was able after eleven years to again cause the dis- 
ease by inoculating an animal with the same splinter. 
The bacilli of tetanus are apparently more numerous 
in certain localities than in others—for example, some 
parts of Long Island and New Jersey, which have 
become notorious for the number of cases of tetanus 
caused by small wounds—but they are very generally 
distributed, as the experiments on animals inoculated 
