130 DISEASES OF CATTLE. 



ing an affected animal that the wound may contain a, germ which 5 if it 

 gain access to a sore or an abraded surface OR yourself, may cause 

 this dreadful disease. 



In summing up the matter it may be said in a very few words that 

 there is a well-grounded belief that the specific germs of tetanus find 

 their way into a wound or an abrasion, where they obtain favorable 

 opportunity for cultivation and increase, and the result of their pres- 

 ence is a poisonous chemical product which is absorbed into the system 

 and causes tetanus. In those cases called idiopathic, where no wound 

 can be found, it docs not require a stretch of the imagination to sup 

 pose that a wound or an injury exists somewhere in the alimentary 

 canal sufficient to harbor the germs, which may have been taken in 

 with the food; and it is even considered possible for the germs to be 

 taken in with the air inhaled and to lodge on a denuded surface of the 

 respiratory tract. 



In this view of the subject there is nothing to do violence to exist- 

 ing knowledge, for it is well known that strychnine in poisonous doses 

 acts on the nervous system in the same manner, causing a spasm simi- 

 lar to tetanus. 



Cattle lead a quieter life and are less subject to wounds than horses 

 and mules, and it may be that they are better able to withstand the 

 effects of the germs, and to these reasons may be due the fact that 

 tetanus is a rare disease in cattle. 



Symptoms. In the description of the nervous system it was ex- 

 plained that sensory impressions are conducted to the brain by the 

 afferent nerves, and the motor impulses are conducted from the nerve 

 center to the muscle (to cause contraction) by the efferent nerves. 

 Now, in describing the symptoms of tetanus, it is well to point out the 

 fact that the motor centers being greatly irritated by the cause of 

 tetanus, an extraordinary stimulus or current is sent to all the mus- 

 cles, which produces a persistent violent contraction or spasm of the 

 muscles. Bearing in mind this fact it is easier to recognize the con- 

 tracted state of the muscles, which are hard and resistant, and stand 

 out prominently as lumps or cords under the skin, especially about the 

 head and neck. 



General sensitiveness is also increased; the afflicted beast is ever on 

 the alert, and is startled by the slightest noise. A harsh voice often 

 brings 011 an increase in the intensity of the spasm ; a touch of the 

 hand, however light, excites fear; clapping the hands or the crack of a 

 whip almost causes the animal to fall. 



The first symptom noticed is usually some stiffness in the manner of 

 carrying the head. The muzzle is elevated "poked out;" the ears 

 are also carried stiffly, and moved very little, if any. The haw or 

 "washer" (meinbrana nictitans) is forced over the eye from the inner 

 corner, and on account of this strange appearance of the eye, many 

 persons who have for the first time seen an animal affected with lock- 



