Lock-jaw 293 



Tetanus, or "lock-jaw," is caused by a germ or bac- 

 terium that usually enters the system through a wound. 

 Once inside, the germs multiply rapidly, and produce 

 violent poison that acts upon the nervous system, 

 causing the voluntary muscles to contract and, at the 

 same time, creating nervous excitement. The germs 

 are believed to be numerous in the soil about barns 

 and stables. They are especially liable to enter wounds 

 of the feet, although any surgical operation or the 

 least break of the skin offers an opportunity for 

 infection. When tetanus occurs without any visible 

 wound, the germs are believed to enter the system 

 through minute wounds, or through a mucous mem- 

 brane, such as the digestive tract. 



Tetanus generally centers in some set of muscles, 

 such as those of the neck, head, jaws, or back, although 

 all the muscles may be more or less affected. The first 

 marked symptom is usually inability to eat, the muscles 

 of the jaws being firmly contracted. The horse be- 

 comes stiff all over; the head is elevated and the nose 

 protrudes; the tail is arched in a peculiar and char- 

 acteristic manner. If forced to move, the animal has 

 a stiff, paddling gait. Great difficulty is experienced 

 in backing the horse. He is easily excited, especially 

 by a slight blow under the jaws. The "haw" is drawn 

 across the inner corner of the eye. The animal grinds 

 his teeth. The affected muscles are rigid to the touch. 

 The flank is usually "tucked up." The animal gives 

 evidence of being seriously ill. 



Put the horse into comfortable and quiet quarters. 

 On no account allow inquisitive visitors to see him. The 



