236 CLINICAL BACTERIOLOGY. 



outbreak of tetanus. If this is removed, for instance by 

 washing with large amounts of water or by exposure to a 

 temperature of 65 C. (149 F.) or by growth of the cul- 

 tures at a temperature of 20 C. (68 F.) or 22 C. (71.6 

 F.) under which conditions the bacilli generate no poison 

 for the first six days such toxin-free bacilli will be in- 

 capable of inducing tetanus.' These views have in general 

 been confirmed. The introduction of toxin-free bacilli does 

 not, as a rule, give rise to infection ; but the spores freed 

 of toxin reacquire their virulence, and tetanus will develop 

 with certainty if with them there are introduced other bacte- 

 ria not giving rise to tetanus, or if simultaneously trauma- 

 tism is inflicted, or a splinter of wood is forced beneath the 

 skin, or, finally, a chemic agent for instance, lactic acid, 

 trimethylamin, etc. is injected at the same time. These 

 experimental data are of the highest importance for a com- 

 prehension of tetanus developing spontaneously. From 

 them the probable conclusion may be drawn that under 

 natural conditions tetanus is not induced by the tetanus- 

 bacilli alone, but that the presence of favoring bacteria 

 thus a mixed infection is necessary, or that a severe trau- 

 matism, or the like, must attend the infection. 



The question has been studied experimentally as to how 

 the extensor spasm arises in cases of tetanus, and whether 

 the tetanus-toxin has a central or a peripheral action. 

 Tizzoni and Vaillard divided all the nerves of an extremity 

 in an animal before inoculation with tetanus. This member 

 remained relaxed, whereas the remainder of the muscular 

 system became rigid. Buschke curarized a tetanized frog, 

 and the tetanus ceased at once. The toxin, thus, can not 

 act upon the muscles themselves or upon the peripheral 

 nerves. After removal of the brain the tetanized frog 

 remained rigid. A direct influence of the poison upon the 

 motor centers through application to the cerebral cortex 

 was without effect upon rabbits. It thus appears that the 

 brain also is not the part attacked by the toxin. Gradual 

 destruction of the spinal cord in tetanized animals causes 

 disappearance of the rigidity in the parts corresponding to 

 the respective sections of the cord. Accordingly, the 

 activity of the toxins appears to be localized in the spinal 

 cord, as is the case also with strychnin. 



The Tetanus- toxin. The germ-free filtrate of a teta- 

 nus-culture from two to four weeks old that has been 



