414 INFECTION AND IMMUNITY. 



phragm, or muscles of the glottis, or from cardiac 

 failure. In some instances the blood has been 

 found more or less laked because of the action of 

 the tetanolysin. 



Tetanus toxin (tetanospasmin) has a very 

 strong affinity for the nervous tissue of susceptible 

 animals. This may be demonstrated in test-tube 

 experiments in which the toxin is mixed with an 

 emulsion of the nervous tissue; the nervous tissue 

 neutralizes the toxin more or less completely, as 

 determined by subsequent inoculations of the mix- 

 ture (Wassermann's experiment). It is held by 

 certain authorities that the toxin attacks only the 

 nervous tissue in man; in some of the lower ani- 

 mals, however, various organs, especially the liver, 

 have an affinity for the toxin. 



The method by which tetanus toxin reaches the 

 central nervous system has been the subject of 

 much speculation and experimentation. Eecent 

 observations by Marie and Morax and by Eansom 

 and Meyer show with a great degree of probabil- 

 ity that it is absorbed by the end organs of the 

 motor nerves and from there passes to the gang- 

 lionic cells through the axis cylinders. This ab- 

 sorption takes place very quickly; when the toxin 

 is given intravenously it disappears from the blood 

 in the course of minutes. It has been found in the 

 nerves within an hour and a half after subcutane- 

 ous injection. Its further transmission centrally 

 occupies more time and, indeed, the investigators 

 mentioned explain the rather long incubation 

 period of the disease on the basis of the time re- 

 quired for this transmission. The brief incuba- 

 tion period in "head tetanus/' accordingly, would 



