TETANUS. 291 



are confined to a well-defined and localized area, and the 

 most careful researches, conducted with the help of both 

 cultivation and histological methods, have hitherto failed to 

 enable any observer to demonstrate the presence of these 

 organisms in the internal organs. It would appear, then, 

 that as in the case of septicaemia and diphtheria, the poison 

 is manufactured by the organisms at the site at which they 

 are actually introduced, and that from this point it is absorbed 

 into the body, and is carried to the special tissues on which 

 it acts. Brieger, indeed, was able to separate from the 

 limb of a patient who had died from tetanus an exceedingly 

 virulent basic poison or ptomaine which he speaks of as tetanin, 

 whilst he also found a very poisonous proteid substance, 

 tetano-toxin, which he called a toxalbumen, a substance of 

 which we shall have to speak in a later chapter. 



At first sight it appears somewhat extraordinary that the 

 development of the tetanus bacillus should be so extremely 

 localized, and that the localization should be confined to a 

 position so near the surface i.e., to the surface of a compara- 

 tively open wound, to which the oxygen of the atmosphere 

 might at first sight appear to have easy enough access. 



When, however, we come to think more carefully of the 

 conditions that prevail in the wound, this does not seem 

 quite so extraordinary. In the first place, there is, covering 

 it, a layer of pus which, as is well known, has little power of 

 holding oxygen in solution, any small quantity that is there 

 being gradually taken up by the leucocytes that escape to the 

 free surface or into the abscess, and utilized by them for their 

 own purposes. Beneath this, especially in the later stages 

 of infiltration, and before the capillary vessels of the granula- 

 tion tissue have begun to form, or are fully formed, the supply 

 of oxygen must necessarily be comparatively small, and any 

 that is present is promptly taken up by the active wandering 

 and proliferating connective tissue cells. Here then we have 

 the conditions under which the tetanus bacillus is enabled to 

 flourish ; there is a condition of anaerobiosis, or oxygen famine. 

 Beyond this, however, where the infiltration is not so great, 

 and where the vessels are considerably dilated, the red blood 

 corpuscles are constantly bringing up their fresh supplies of 

 oxygen to the tissues, and in consequence the fluids at some 

 little distance from the wound contain more oxygen than 

 there is near the surface of the wound, and the conditions 



