CHAPTER XVI. 



ACTINOMYCES. 



IN cattle there occurs a fatal disease, which is characterised 

 by the formation of firm nodules of various sizes, due to a 

 growth of small cells. In the centre of the nodules lie 

 dense groups of peculiar club-shaped corpuscles actinomyces 

 radiating from a firm homogeneous centre, and joined to 

 this by longer or shorter, single or branched, filamentous 

 stalks. Each of these actinomyces-corpuscles appears homo- 

 geneous, and of a bright slightly greenish lustre. These 

 masses consist of what is called Actinomyces (Bellinger), and 

 the disease is termed actinomycosis. 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 

 induration of the tongue "wooden tongue." On making 

 sections through this latter organ there are found present in 

 all parts microscopic tumours of small-cell growth. In the 

 centre of each tumour is a clump of actinomyces. This 

 clump is surrounded by a zone of largish cells, with one to 

 four nuclei, The periphery of the tumour is made up of a 

 fibrous capsule, with spindle-shaped cells. Occasionally the 

 tumours are to be seen also in the skin and in the lung ; in 

 the latter organ they appear as whitish nodules, easily 



