TUMOURS AND CANCERS. 235 
which form perceptible nodules. Many nodules becom- 
ing confluent give rise to a tumour in the affected part. 
That the actinomyces is the cause of the disease is demon- 
strated by the fact that the fungus may be cultivated 
artificially, and when introduced into a calf experi- 
mentally will produce the disease. 
Actinomycosis is interesting pathologically, but is also 
important from an economical point of view, and still 
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Fic. 119.—-A tuft of Actinomyces highly magnified, showing the 
clubs. 
more important in a sanitary respect, as quite a number 
of cases have been placed on record in this country, but 
more especially in Germany, which have occurred in the 
human subject, and it is a noteworthy fact that in many 
of the patients the disease seems to have commenced in 
the alimentary canal. 
Sarcomata.—Those tumours which pathologists term 
sarcomata differ from those produced by the ray-fungus 
