448 Tetanus. 



this each toxin molecule is composed of one non-toxic (haptophore) 

 and one toxic (toxophore) atom group. The protoplasm of the motor 

 nerve cells is composed of a vital nucleus and numerous side chains 

 (receptors), of which mam- possess a special affinity for the haptophore 

 atom groups of the toxin molecule. AYhen such molecules of the tetanus 

 toxin reach the nerve cells they are anchored by the aid of haptophore 

 groups to the corresponding receptors of the cell protoplasm, -whereupon 

 the toxophore group attack the vital nucleus of the cell. The opposed 

 affinity between tetanus toxin and nerve substance is demonstrated 

 by the experimental observation, where it is shown that a mixture 

 of toxin and brain substance is non-toxic for guinea pigs (Wassermann 

 & Takaki). 



Ehrlich also demonstrated a hemolytic substance (tetanolysin) in 

 culture filtrates, which was neutralized by antitetanic serum. 



Recovery from one infection does not immunize the animal 

 against a subsequent one. Repeated occurrence of the disease 

 may result from renewed infection, or may follow when tetanus 

 spores were retained somewhere, as for instance in a scar, in an 

 abscess or blood coagulum and germinate at a considerably 

 later date. (Repeated infection in horses ^vas observed by 

 Johne after 4, Hill after 5, Hell after 6, Mongnean after 10 

 months.) 



Anatomical changes. Autopsy reveals no changes charac- 

 teristic of the disease. In the central nervous system, especially 

 in the spinal cord and its coverings, hyperemia is often seen 

 and punctate hemorrhages are found in the gray matter of 

 the brain, but such findings are not uncommon in other dis- 

 eases. This is also true of the microscopic examination of 

 the motor nerve cells which show slight degenerative vacuoles, 

 disappearance of N'issl's bodies, etc. Marinesco found marked 

 changes also in the nerve fibrils; in many cases, hoAvever, the 

 appearance was entirely normal and the positive findings may 

 be associated with the infections accompanying w^ounds. Small 

 hemorrhages and serous infiltration are frequently found in 

 the peripheral nerves, especially in those leading from the 

 infected area. Fatty degeneration of the heart muscle is an 

 almost constant occurrence. The intramuscular connective 

 tissue of the trunk and the extremities is edematously infiltrated 

 and contains small hemorrhages, with muscle bundles torn and 

 colored yellow^ or grayish due to parenchATiiatous or hyaline 

 degeneration. (Eichhorn found the muscles in a cow to look 

 like fish meat.) 



In animals in which rigor mortis sets in early the only 

 lesions are those pointing to death by suffocation (dark color 

 of the poorly coagulated blood, slight hemorrhages on the 

 serous and mucous membranes, hyperemia and acute edema of 

 the lungs) and in addition occasional subsequent changes 

 (pneumonia, bone fractures, signs of general septic infection). 



The Rife of infection should if possible he fliscloserl in every ease at autopsy. 

 and this requiiea at times a very careful examinatiou of all the parts of the body 



