Pathogenesis 347 



The lockjaw or trismus and the opisthotonos that are so charac- 

 teristic of the affection depend, according to Zupnik's view, upon a 

 loss of equilibrium among the muscles affected. They occur only 

 in descending tetanus and depend upon spasm of muscles without 

 equally powerful opposing groups. The stronger muscles of the jaw 

 are those that close it; the stronger muscles of the back, those of the 

 erector group. This view is exactly the opposite of Meyer and Ran- 

 som,* who believe that the tetanus toxin is absorbed only along the 

 nerve trunks, and found that section of the spinal cord prevented 

 the ascent of tetanus from the lower extremities. Injection of the 

 toxin into a posterior nerve-root produced tetanus dolorosus. In- 

 jection of the toxin into a posterior nerve-root together with section 

 of the spinal cord produced exaltation of the reflex irritability — 

 " Jactationstetanus." Injection in sensory nerves does not produce 

 tetanus dolorosus because the transportation of the poison along 

 these trunks is so slow. 



The tetanolysin is a hemolytic component of the toxic bouillon, 

 and is entirely separate and distinct from the tetanospasmin or con- 

 vulsive poison. It probably takes no part in the usual clinical 

 manifestations of tetanus. 



Pathogenesis. — The work of Kitasato has given us very complete 

 knowledge of the biology of the tetanus bacillus and completely 

 established its specific nature. 



When a white mouse is inoculated with an almost infinitesimal 

 amount of tetanus culture, or with garden earth containing the tet- 

 anus bacillus, the first symptoms come on in from one to two days, 

 when the mouse develops typical tetanic convulsions, first beginning 

 in the neighborhood of the inoculation, but soon becoming general. 

 Death follows sometimes in a very few hours. In rabbits, guinea- 

 pigs, mice, rats, and other small animals the period of incubation is 

 from one to three days. In man the period of incubation varies 

 from a few days to several weeks, and averages about nine days. 



The disease is of much interest because of its purely toxic nature. 

 There is usually a small wound with a slight amount of suppuration 

 and at the autopsy the organs of the body are normal in appearance, 

 except the nervous system, which bears the greatest insult. It, 

 however, shows little else than congestion either macroscopically or 

 microscopically. 



The conditions in the animal body are in general unfavorable to 

 the development of the bacilli, because of the loosely combined 

 oxygen contained in the blood, and they grow with great slowness, 

 remaining localized at the seat of inoculation, and never entering the 

 blood. Doubtless most cases of tetanus are mixed infections in 

 which the bacillus enters with aerobic bacteria, that aid its growth 

 by absorbing the oxygen in the neighborhood. The amount of 

 poison produced must be exceedingly small and its power tremen- 

 * "Archiv. f. exper. Path. u. Pharmak.," 1903, Bd. xlix, p. 396. 



