ACTINOMYCOSIS "AH'/ 



Pathogenesis. — The disease in man corresponds pretty 

 closely to that observed in animals, but there is less 

 tendency to localisation, by the abundant formation of 

 connective tissue and the frequency of calcification. The 

 tendency of the disease in man is to become chronic, and 

 it is only by the implication of some vital organ, or by 

 the exhaustion following prolonged suppuration, that the 

 patient succumbs. The disease spreads by continuity, 

 and no tissue seems able to resist its invasion. Besides 

 this, second embolic foci may occur, perhaps the commonest 

 seat being the liver. No doubt many cases have gone 

 unrecognised in days gone by, and have been certified as 

 due to pyaemia ; but the actinomyces is not greatly inclined 

 to suppuration, and where it is kept free from contamination 

 by other organisms, as in the case of an actinomycosis 

 lesion occurring in the cranium, it may remain almost 

 dormant for long periods. The disease does not extend by 

 the lymphatic system, and is characterised by the appear- 

 ance of a chronic swelling, which gradually enlarges, softens, 

 and inclines to approach the surface, when fluctuation is 

 sometimes to be felt. The skin becomes bluish-red, as 

 over a chronic abscess, and eventually a small yellow point 

 forms, and a yellow serous or pus-Hke fluid escapes ; and in 

 this discharge the yellow granules will be visible. If a 

 little of this fluid be allowed to run gently down the side of 

 a test-tube, which is then held up to the light, the small 

 yellow grains will be visible, which may be picked out, 

 placed on a slide, and pressed down with a cover-glass. It 

 will transmit to the finger a sensation similar to that of 

 squeezing a drop of solid fat, if the granule was taken 

 from man ; ,while if from an animal, the granule is more 

 gritty, from calcareous degeneration. On examining the 

 slide with a low power, a number of ovoid, kidney-shaped 

 masses are seen, which with a higher power show the 



