382 TETANUS. 



of sections may show at the edges of the wound necrosed tis- 

 sue in which the tetanus bacilli may be very numerous. If a. 

 scraping from the wound be examined microscopically, bacilli 

 resembling the tetanus bacillus may be recognised. If these 

 have spored, there can be practically no doubt as to their 

 identity, as the drumstick appearance which the terminal spore 

 gives to the bacillus is not common among other bacilli. Care 

 must be taken, however, to distinguish it from other thicker 

 bacilli with oval spores placed at a short distance from their 

 extremities, such forms being common in earth, etc., and also 

 met with in contaminated wounds (Fig. 126). It is important to 

 note that the wound through which infection has taken place 

 may be very small, in fact, may consist of a mere abrasion. In 

 some cases, especially in the tropics, it may be merely the bite 

 of an insect. The absence of a definite channel of infection 

 has given rise to the term "idiopathic " tetanus. There is, how- 

 ever, practically no doubt that all such cases are true cases of 

 tetanus, and that in all of them the cause is the B. tetani. The 

 latter has also been found in the bronchial mucous membrane 

 in some cases of the so-called rheumatic tetanus, the cause of 

 which is usually said to be cold. 



The pathological changes found post mortem are not striking. 

 There may be haemorrhages in the muscles which have been the 

 subject of the spasms. These are probably due to mechanical 

 causes. Naturally it is in the nervous system that we look for 

 the most important lesions. Here there is ordinarily a general 

 redness of the grey matter, and the most striking feature is the 

 occurrence of irregular patches of slight congestion which are 

 not limited particularly to grey or white matter, or to any tract 

 of the latter. These patches are usually best marked in the 

 grey matter of the medulla and pons. Microscopically there is. 

 little of a definite nature to be found. There is congestion, and 

 there may be minute haemorrhages in the areas noted by the 

 naked eye. The ganglion cells may show appearances which 

 have been regarded as degenerative in nature, and similar 

 changes have been described in the white matter. The only 

 marked feature is thus a vascular disturbance in the central 

 nervous system, with a possible tendency to degeneration in its 

 specialised cell. Both of these conditions are probably due to 

 the action of the toxins of the bacillus. In the case of the 



