2o8 ACTINOMYCOSIS 



must attain to a certain stage or period in its development 

 before it will live and multiply in living animal tissues. It 

 has been observed that, as a rule, cattle become infected when 

 they are kept upon dry food. 



§ 165. Symptoms. Actinomycosis is manifested by a 

 firm swelling or tumor usually situated in the region of the 

 head or throat. It is first recognized as a slight swelling of 

 the affected part resembling somewhat the result of a bruise. 

 It is stated by those wdio have had much experience with the 

 disease that many cases of actinomycosis seem to be caused by 

 blows or injuries received while struggling in stanchions. The 

 enlargement gradually increases in size and ordinarily it is 

 well defined from the surrounding tissues. 



Upon manipulation the tumor feels hard and dense and if 

 it is not the result of the bulging of the adjacent bone it is 

 usually attached to it. In the region of the throat it may be 

 fluctuating. After a variable length of time, the tumor may 

 soften in one or more places, rupture and discharge a rather 

 thick, yellowish and more or less sticky, purulent substance. 

 The discharge may continue or, as often happens, the opening 

 heals temporarily only to discharge again. The discharge often 

 takes place into the cavity of the mouth or throat. Sometimes 

 the neoplastic tissue increases in amount until it gradually 

 forces its way through the opening resembling somewhat a 

 cauliflower in appearance. The actinomycotic growth fre- 

 quently increases rapidly in size after it has discharged. In 

 later stages the teeth may become ulcerated and loose. 



When the tongue is affected the animal finds it difficult to 

 eat. The organ is swollen and in advanced cases hangs from 

 the mouth with abundant salivation. When the pharynx is 

 affected there is difficulty in swallowing and when the larynx 

 is attacked there is difficulty in breathing. In this countr}^ 

 the tumor is most frequently seen on the external surface of 

 the jaw. It is stated by Salmon that it usually begins in the 

 connective tissue beneath the skin but soon extends to the bone 

 which it penetrates. Actinomycosis of the cervical vertebrae 

 may cause spinal paralysis. When the lungs are attacked the 

 animal may present the appearance of one suffering from a 

 chronic pulmonary disease such as tuberculosis. 



