172 BACTERIA 



apparatus. Death is caused either by a spasm of the glottis or 

 diaphragm, or by cardiac failure and exhaustion. A local mani- 

 festation merely affecting certain groups of muscles may occur. 

 Laking of the blood by tetanolysin found in the bodies dead from 

 tetanus is a well known phenomenon. In fatal cases, toxin may 

 be demonstrated in the bladder by injecting the urine into mice, 

 causing in them tetanic symptoms. Various groups of muscles are 

 affected in tetanic seizures. The muscles of the jaw, if affected, 

 cause trismus; if those of the back are involved the individual suffers 

 from opisthotonos. The seizures may be constant or tonic; or 

 convulsive and violent, then they are designated as clonic. 



Immunity. Metchnikoff claims that the only natural immunity 

 possessed by man against tetanus resides in his leucocytic powers 

 of defense. Susceptibility of the natural receptors of the nerve 

 cells for the toxin, and the degree of affinity, constitutes the cause 

 of intoxication, its degree, and ultimate result. Affinity for the 

 receptors of other less vital organs, on the part of the toxin, estab- 

 lishes a means of natural defense. Acquired immunity is dependent 

 upon the formation of anti-toxin. The anti-toxin, formed by suscep- 

 tible animals injected with tetanus toxin, is chiefly useful and valu- 

 able as a prophylactic measure. An epidemic of puerperal tetanus 

 in a lying-in hospital was checked by its use. Sprinkling dry pow- 

 dered anti-toxic serum on wounds infected with tetanus bacilli, or 

 toxin, prevented infection (Calmette and McFarland). The anti- 

 toxin may be injected either into the substance of the brain in cases 

 of well developed tetanus, or into* the cerebro-spinal fluid, in the 

 hope of neutralizing the toxin not already in firm combination with 

 the nervous elements. Large nerves near the infecting wound may 

 be injected with anti-toxin in the hope of binding the toxin already 

 in combination with the nerve cells. 



Female mice immunized against tetanus toxin, transmit a great 

 amount of immunity to their off-spring. The milk of an immunized 

 mouse also causes a passive immunity in other young that are 

 suckled by her. 



