304 Veterinary Medicine. 



marked feature, so that if the patient is not speedily killed by 

 dyspnoea, it soon perishes from starvation and exhaustion. 



The cause of death is usually asphyxia, hyperpyrexia, or exhaus- 

 tion. 



Lesions. There are no constant or pathognomonic structural 

 changes in tetanus. Those that are found are inconstant and as 

 a rule secondary. A wound (entrance channel) can usually be 

 made out, often in the region of the foot, or in connection with 

 castration. In the new born there is the unhealed navel, and in 

 parturient cows the catarrhal, septic or injured womb. In the 

 seat of such wound may be found the foreign body (nail, splinter, 

 etc.), and some pus or simple congestion or even necrosis. The 

 nerve trunks leading from such infected wound may be hyper- 

 semic. The presence of the bacillus in the wound may be deter- 

 mined by microscopic examination or inoculation on a .small 

 animal. 



The changes in the nerve centres may be congestion of the 

 horns of gray matter, and there may be slight haemorrhage, 

 exudation, especially shown in the encrease of the cerebro-spinal 

 fluid, softening, cell proliferation, and granular invasion of the 

 nervous tissue. In .separate cases the myelon, the corpus striatum 

 and the cerebellum have .shown le.sions. The meninges are occa- 

 sionally hyperaemic. Spinal lesions have been noted especially 

 in the bulbo-cervical and lumbar regions. Exceptionally in the 

 horse there are blood extravasations from fractures or dislocations 

 of the vertebrae. 



In subjects dying of asphyxia the lungs and right heart are 

 congested, and the blood may be black, only loosely coagulable 

 and with free haemoglobin. There is congestion of the intestinal 

 as of the respiratory mucosa, and also of the liver, spleen and 

 kidneys. The congested bladder usually contains urine contrary 

 to what is the case in rabies. 



Diagnosis. From strychnia poisoning tetanus is distinguished 

 by the gradual and progressive approach of the spasms and by 

 the absence of the intervals of complete relaxation which separate 

 the rapidly recurring and violent .spasms of strychnia. In tetanus 

 the spasms may be modified but never completely intermitted, and 

 more or le.ss stiffness, trismus and protrusion of the haw constantly 

 persist. In strychnia too, the paroxysm is far more intense than 



