258 A MANUAL OF BACTERIOLOGY 



ACTINOMYCOSIS. 



This disease attacks cattle and occasionally man 

 himself. It is caused by the ray-fungus or Actino- 

 myces. 'In cattle the disease manifests itself by 

 firm tumours in the jaw, in the alveoli of the teeth, 

 and particularly by a great enlargement and indura- 

 tion of the tongue 'wooden tongue' Occasionally 

 these tumours occur in the skin and lungs. The 

 ray-fungus has been cultivated on solid ox-serum, 

 and when pure cultures are injected into animals 

 they give rise to actinomycosis. 



THRUSH. 



This disease is caused by the fungus O'idium albi- 

 cans. It is found on the mucous membrane of the 

 mouth of infants, causing white patches on the 

 tongue, gums, and soft palate. Like the higher 

 fungi, this plant is composed of hyphse and spores, 

 which take root in the mucous lining of the mouth. 

 The spores are produced by the division of the ter- 

 minal cells, or sometimes by endogenous formation 

 within the hyphse. 



In concluding the present chapter we may say 

 that most infectious diseases have a microbian 

 origin, but there are some (e.g. typhus fever, whoop- 

 ing-cough, mumps, etc.) in which no microbes have 

 been isolated and cultivated apart from the body ; 

 and there are other infectious diseases which owe 

 their origin to small animal organisms, known as 



