BACILLUS TETANI 479 



time in the blood of these animals before it is excreted. Donitz 1 

 and Knorr 2 have shown that tetanus toxin disappears rather rapidly 

 from the blood stream of susceptible animals, on the contrary, and 

 almost coincidently with its disappearance the symptoms become 

 manifest. Wolff 3 states that the injection of tetanus toxin into experi- 

 mental animals in small doses produces a lymphocytosis. 



How Tetanus Toxin is Absorbed. The brilliant researches of Meyer 

 and Ransom 4 have shown that tetanus toxin is absorbed by the per- 

 ipheral nerve end-organs and travels along the axis cylinders of the 

 nerves to the central nervous system. The spasms, which are 

 characteristic of tetanus, are supposed to be of central origin, and the 

 experiments of Gumprecht 5 would suggest that this is the case. He 

 cut the motor nerves to a limb and thus prevented the tonic contrac- 

 tions in that part. Zupnik 6 believes that the spasms may be either of 

 peripheral or central origin, the symptoms elicited depending largely 

 upon the reflex irritability of the medulla or cord. This view has not 

 been substantiated. 



Tetanus Antitoxin. The injection of tetanus toxin in very small, 

 sub-fatal doses, which are gradually increased, or of toxin weakened 

 by chemicals, as iodine trichloride, induces immunity in horses or 

 other susceptible animals, which is manifested by the gradual appear- 

 ance of a specific antitoxin in the blood. This antitoxin will neutralize 

 tetanus toxin both in vitro and in vivo; it will prevent the development 

 of tetanus in experimental animals, provided it is given before or 

 immediately following the injection of toxin. Donitz 7 has shown 

 that as many as twelve fatal doses of toxin may be neutralized -jby 1 

 c.c. of a 0.001 to 0.002 dilution of antitoxin, provided the toxin and 

 antitoxin are mixed before injection. Four minutes after injection 

 of 1 c.c. of toxin, 1 c.c. of 1 to 600 dilution of antitoxin is required for 

 neutralization; eight minutes after injection of the same amount of 

 toxin, 1 c.c. of 1 to 200 dilution of antitoxin is required to protect the 

 animal, and fifteen minutes after the injection of 1 c.c. of toxin, 1 

 c.c. of 1 to 100 dilution of antitoxin is required. These experiments 

 illustrate clearly the necessity of administering tetanus antitoxin at 

 the earliest possible moment to obtain favorable results. 



Inasmuch as the toxin appears to reach the central nervous system 



1 Deutsch. med. Wchnschr., 1897, No. 27. 



2 Miinchen. med. Wchnschr., 1898, Nos. 11 and 12. 



3 Berl. klin. Wchnschr., 1904, xli, 1273. 



4 Arch. f. exp. Pharm. u. Path., 1903, xlix, 369. 5 Pfliiger's Archiv, 1895. 



6 Deutsch. med. Wchnschr., 1900, 837. 7 Ritchie, Jour, of Hyg., ii. 



