Tetanus. 341 



affirmed as constant. Neuritis in the region of the wound is 

 sometimes found, especially if the lesion is a contused or painful 

 one. 



The muscles often show lesions, the result of the violent con- 

 tractions. There may be points of ecchymosis and partial rupt- 

 ure of individual fibres, they may be of a deep red, or again 

 pale, soft, and as if parboiled. There may be hypersemia or 

 oedema of the lungs, congestion of the larynx, ecchymosis on the 

 pericardium and other serous and mucous membranes, and con- 

 gestion of the liver, spleen and kidneys. Rigor mortis sets in 

 rapidly and is usually very persistent. The muscles contain an 

 excess of lactic acid. 



Accessory Causes. Whatever contributes to traumas must be 

 classed in this list. Solipeds, work oxen and dogs are especially 

 Exposed in this sense. In all animals, castration wounds ; in 

 horses and lambs, amputation of the tail ; in solipeds, pricks, 

 bruises and fistiilse of the feet ; all kinds of surgical wounds ; in 

 females, the parturient condition ; and in the new born, the um- 

 bilical sore form infection atria. The tendency to infection in 

 wounds of the feet in animals, and of the hands and feet in man, 

 is easily explained by contact with the virulent earth or dust. 

 Children running barefoot, or injuring their bare knees and sol- 

 diers sleeping on the ground are similarly exposed. The con- 

 tamination of the clothes is the main condition. It has been held 

 that infection never takes place from the gastro-intestinal canal, 

 but the facts that the bacillus is frequently present in the prima 

 vise and that the mucosa is often perforated by blood-sucking 

 parasites, suggest that some cases (idiopathic) are probably due 

 -to intestinal infection. The gland ducts also and the follicles of 

 Peyers' patches and of the solitary glands offer available fields 

 for the colonization of the bacillus and for infection. 



General Symptoms in Animals. In experimental cases, in 

 -which there has been a large intravenous injection of the blood 

 ■of a victim of tetanus, the symptoms may set in speedily and 

 violently. In casual cases, however, there is usually an incubation 

 period varj'ing on an average from three to fifteen days in the 

 Jiorse while it may be as short as two days in cow and sheep. 

 Hoffmann quotes one incubation in the horse as but six hours 

 after a wound in the neck, and another as twenty-five days, fol- 



