516 THE ANAEROBIC BACTERIA 
place in vitro. The spleen, liver, kidney and other non-nerve-contain- 
ing tissue have little or no neutralizing power for tetanus toxin. 
MetchnikoflF' and BlumenthaP have determined experimentally that the 
brain tissue of pigeons and hens, which are almost refractory to tetanus 
toxin, possess but little neutralizing power for it.'^ x\sakawa^ has 
corroborated these results and has also shown that the toxin may cir- 
culate for some time in the blood of these animals before it is excreted. 
Donitz^ and Knorr'' 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 and von Torday^ state that the injection of tetanus 
toxin into experimental animals in small doses produces a lympho- 
cytosis. 
How Tetanus Toxin is Absorbed.— The brilliant researches of Meyer 
and Ransom^ have shown that tetanus toxin is absorbed by the periph- 
eral nerve end-organs and travels along the axis cylinders of the 
nerves to the central nervous system. The spasms, which are charac- 
teristic of tetanus, are supposed to be of central origin, and the experi- 
ments of Gumprecht'' would suggest that this is the case. He cut the 
motor nerves to a limb and thus prevented the tonic contractions in 
that part. Zupnik^*^ 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 sub- 
stantiated. 
Tetanus Antitoxin.— The injection of tetanus toxin in very small, 
subfatal doses, which are gradually increased, or of toxin weakened 
by chemicals, as iodine trichloride or formalin, induces immunity in 
horses or other susceptible animals, which is manifested by the gradual 
appearance of a specific antitoxin in the blood. This antitoxin will 
neutralize tetanus toxin both in vitro and in vim; it will prevent the 
development of tetanus in experimental animals, provided it is given 
1 Ann. Inst. Pasteur, 1898, 12, 81. 
2 Deutsch. med. Wchnschr., 1898, 24, 185. 
3 There appears to be some combining power of the brain tissue of relatively non- 
susceptible animals, as hens and pigeons, for tetanus toxin, however. A possible explan- 
ation for this phenomenon is furnished by Miiller (Centralbl. f. Bakteriol., orig., 1903, 
34, 567). He found that lipoids would combine with tetanus toxin at least to a limited 
degree. Loewe (Biochem. Ztschr., 1911, 33, 225; 34, 495) has shown that tetanus toxin 
will unite not only with lipoids but with fats and similar substances. Marie and Tiffeneau 
(Ann. Inst. Pasteur, 1908, 22, 289, 644) have discovered that although a small amount 
of tetanus toxin may be bound by lipoidal substances in the brain in susceptible animals, 
the greater part of it is bound by albuminous substances. They believe that the essential 
albuminous substances necessary for this union are absent or inactive in non-susceptible 
animals. 
< Centralbl. f. Bakteriol., 1898, 24, 166. 234. 
5 Deutsch. med. Wchnschr., 1897, 23, 428. 
6 Miinchen. med. W^chnschr., 1898, 45, 321, .362. 
7 Berl. klin. Wchnschr., 1904, 41, 1273. 
8 Arch. f. exp. Pharm. u. Path., 1903, 49, .369. 
9 Pfluger's Archiv., 1895, 59, Heft 3-4. 
'" Deutsch. med. Wchnschr., 1900, 26, 837, 
