TETANUS. 671 



Nicolaier's bacillus assumes the form of a straight rod, one end of 

 which is swollen by the presence of a spore. It is anerobic, grows in 

 a number of different media, most rapidly at a temperature of 100" to 

 102° Fahr. (38° to 39° C), and stains well by Gram's method. 



Though quite common in the horse, tetanus is rare in other 

 domestic animals. 



In the ox it may result either from mechanical injuries, suppu- 

 rating sores, or surgical operations. In the cow, goat, and sheep it 

 sometimes assumes the form of a true enzooty after parturition if the 

 byres, etc., are not disinfected. In male animals it principally follows 

 castration by one of the cutting methods, and in lambs is seen after 

 amputation of the tail. A large number of animals belonging to one 

 flock may be affected, and Moussu has known two-thirds of a given 

 number of castrated lambs to die of tetanus. 



Despite the sensitiveness of domesticated animals to tetanic infec- 

 tion they may all be protected, either by injections of cultures, or by 

 gradually increasing injections of specific toxin. The latter, however, 

 are more efficacious when modified by the addition of terchloride of 

 iodine or of iodine water. The blood of immunised subjects rapidly 

 acquires antitoxic powers, which may be greatly increased for the pur- 

 pose of obtaining anti-tetanic serum. 



The symptoms of tetanus are the same in all species. 



In the first stage the animal appears stiff, walks in a jerky way 

 and holds the head high, with the ears pricked. The eyes are 

 slightly withdrawn into the orbits, and the animal shows marked 

 general excitability. 



In the second stage there are muscular contractions, together with 

 trismus, stiffness of the neck, limbs and vertebral column, spasm of 

 the spinal muscles and muscles of the limbs (tonic contraction), and 

 the animal has a peculiar, staring look. 



In the third stage mastication becomes difficult or impossible, 

 respiration is impeded, and the animal suffers from spontaneous 

 attacks of muscular contraction or from attacks due to external 

 stimulation (noises, sudden movements, changes from darkness to 

 light, etc.). 



In the fourth stage the animal is. liable to fall, asphyxia threatens, 

 and death occurs from respiratory syncope. 



Recovery is quite exceptional in the sheep, goat, and ox; death 

 usually occurs between the second and sixth days. 



Diagnosis. Tetanus being less common in the ox, sheep, and goat 

 than in the horse, the diagnosis is not so easy in these animals, but 

 as it develops under different conditions, and as it usually attacks 

 several animals in one byre or fold, the diagnosis is rarely very 



