TETANUS, 489 



the disease advances it becomes accelerated, harder, and more 

 incompressible. When the spasm becomes general, tlie position 

 of the various parts of the body is regulated by the action of 

 tlie more powerful muscles. The limbs are extended, flexion of 

 them is peiformed with difficulty, and the patient stands with 

 outstretched limbs. The course of the levator humei'i can be 

 easily traced, and the contraction of this, and other muscles 

 which act upon the superior part of the cervical region, 

 cause the neck to assume the appearance of what is termed 

 " ewe neck." The peristaltic motion of the bowels is stopped ; 

 the urinary bladder firmly contracted ; a dry, husky cough 

 comes on when the animal attempts to swallow, and the act of 

 deglutition is performed with a difficulty which increases Irom 

 day to day. The muscles of the abdomen are rigid ; the belly 

 looks small and hard ; the intercostals act imperfectly ; and 

 when the diaphragm becomes involved, the breathing is per- 

 formed with very great difficidty. 



Although the spasm of tetanus is of the tonic or persistent 

 kind, there are exacerbations of a clonic intermittent character ; 

 and the whole coiirse of the disease is marked by paroxysms of 

 great severity if the animal be subjected to meddling attendance, 

 strong light, or rustling noises. In a modified light, and when 

 the animal is kept quiet, the spasms are usually diminished, and 

 the exacerbations much milder. 



But little is known about the general pathology of tetanias. 

 ,Some writers are of opinion that it is due to an exalted polarity 

 of the nervous centres, excited by the injury in the traumatic 

 form, or resulting from a mal-condition of the blood, or the 

 effects of cold acting upon the nerves of sensibility in the idio- 

 pathic form of the disease. 



For many years, however, it was suspected by many English 

 veterinarians, that tetanus was both a contagious and infectious 

 disease. The contagiousness of tetanus has now been almost 

 conclusively proved, the disease having been transmitted by 

 inoculation, particularly with material obtained from the spinal 

 ■cord of tetanic subjects. 



The contagiousness of the disease is due to a micro-organism 

 — the Bacillus tetani — described by Nicolayer, 1884, and by 

 Hosenbach, which gives rise to the formation of a ptx)maino 

 termed Tetanine. This or^auism i^ longer but iiarrower than 



