TETANUS 239 
of the trouble with the respiratory muscles. Thus congestion, edema, 
hemorrhages, pneumonia, emphysema and hypostatic congestions 
have been described. In the heart there are usually epi- and endo- 
cardial hemorrhages. The fibers of the muscles may show cloudy 
swelling and the various organs may be more or less affected. The 
specific lesions are those in the nerve cells. It is believed that the 
toxin elaborated at the point of infection reaches the cells of the 
central nervous system through the nerves themselves. The toxin is 
diffused very slightly through the blood. Tetanus toxin as demon- 
strated by Wasserman and Takaki has a special affinity for the nerve 
cells. The toxin becomes fixed, after the lapse of some hours, by 
the cells of the central nervous system and it is then that the symptoms 
begin. It is because of this affinity that the therapeutic value of 
tetanus antitoxin is not greater. The antitoxin neutralizes the toxin 
circulating in the blood but it is ineffective against existing lesions. 
Diagnosis. ‘Tetanus is to be diagnosed very largely by the symp- 
toms. The microscopic examination of the local lesion, if it can be 
found, might reveal the tetanus bacillus. There are no specific tests 
that can be relied upon. The injection of guinea pigs with a small 
quantity of the blood of the suspected animal can be resorted to if 
desired. It would, in case of tetanus, produce symptoms. Cour- 
mount has shown that normal horse serum agglutinates tetanus 
bacilli feebly (1 to 50 to 1 to 100). The serum from highly immunized 
horses agglutinates in dilutions of 1 to 2000 and sometimes higher. 
Tetanus is to be differentiated from rabies, acute muscular rheu- 
matism, eclampsia, catalepsy, strychnine poisoning, convulsions in 
the newly born and pyemic polyarthritis in lambs and foals. It 
must be distinguished from tetany due to the traction of certain 
nerves adhered in a cicatrix. 
The symptoms of tetanus that are the most diagnostic are the con- 
tinuous tonic spasms of different groups of muscles, the apparent 
clearness of mind (if we may attribute such a quality to animals), and 
the absence of fever in the beginning of the symptoms. The general 
attitude of the animal is also of much value. Poisoning with strych- 
nine usually occurs in dogs where tetanus is rare, and again in strych- 
nine poisoning the suddenness of the attack, the rapidity of the course 
and the increased reflex irritability are valuable diagnostic features. 
In differentiating tetanus from other affections in the newly born, the 
microscopic examination of cover-glass preparations made from the 
end of the umbilicus may be of assistance. 
