TETANUS— LOCK-JAW 575 



snap again and again at that which has no real existence. Then will come 

 the iri-epressible desire to bite tlie attendants or the animals within its reach. 

 To this will succeed the demolition of the rack, the mangei', and the whole 

 furniture of the stable. Towards the close of the disease there is generally 

 paralysis, usually confined to the loins and the hinder extremities, or involv- 

 ing those organs which derive their nervous influence from this portion of 

 the spinal cord ; hence the distressing tenesmus which is occasionally seen." 

 How paralysis can produce tenesmus is not very clear, but of the very general 

 existence of this symptom there can be no doubt. 



A craving thirst with inability to drink may be a symptom, or, as in some 

 instances, a spasm may be induced by the sound of the bucket. Whenever, 

 therefore, these symptoms follow upon the bite of a dog, unless the latter is 

 unquestionably in good health, rabies may be suspected, and the bare sus- 

 picion ought always to lead to the use of the bullet, which is the safest way 

 of killing a violent horse.^ There is only one disease {jjhrenitis) Avith which 

 it can be confounded, and in that the absence of all consciousness and, in 

 milder cases, of fear, so that no moral control whatever can be exercised, 

 marks its nature, and clearly distinguishes it from rabies, the victim to which 

 is conscious to the last, and though savage and violent in the extreme, is 

 aware of the power of man, and to some extent under his influence. 



TETANUS-LOCK-JAW 



Tetanus, one form of which is known as lock-jaw, has its seat apparently 

 in the nervous system, but like many other diseases of the same class, the 

 traces it leaves behind are extremely uncertain, and are displayed moi'e on 

 the secondary organs, through which it is manifested, than on those which 

 w^e believe to be at the root of the mischief. Thus the muscles, which have 

 been long kept in a state of spasm, show the marks of this condition in their 

 softened and apparently I'otten condition. They, in fact, have had no interval 

 of rest, during which nutrition could go on, and have lost much of the 

 peculiarity of structure which enables them to contract. 



The stomach often shows marks of inflammation, but as all sorts of violent 

 remedies are employed, this may be due to them rather than to idiopathic 

 disease. The lungs also are generally congested, but here, like the state of 

 the muscles, it may be a secondary effect of the long-continued exertions of 

 the latter, which nothing but the absence of all important lesions of the 

 brain and spinal cord would induce the pathologist to pay the slightest 

 attention to. It almost always follows some operation, or a severe injury 

 in which a nerve has been implicated, the most frequent causes being the 

 piercing of the sole by a nail, or a prick in shoeing, or the operations of 

 docking, nicking, castration, or accidental injuries, as broken knees. 



Tetanus is now known to be due to a specific microbe, the tetanus 

 bacillus, and can be cultivated in the usual media and reproduced with 

 certainty. 



The Symptoms are a permanent rigidity of certain voluntary muscles, and 

 especially of the lower jaw (whence the popular name, lock-jaw). The mouth 



^ As rabies is now known to run its course and end fatally in less than ten days, the 

 afflicted horse may be given the benefit of the doubt, provided he is rendered secure 

 against inflicting injury upon his attendants or other animals. 



