618 APPENDIX. 
tagious, but infection may result from the ingestion of 
vegetable products which contain the fungus. The 
cereal grains, which from their nature are capable of 
‘ penetrating the tissues, have been repeatedly found in 
centres of actinomycotic infection. This usually occurs 
in the vicinity of the mouth, where injuries have been 
accidentally caused. The micro-organism may also be 
introduced by means of carious teeth. Cutaneous in- 
fection has been produced by wood-splinters, and infec- 
tion of the lungs by aspiration of fragments of teeth 
containing the fungus. The further distribution of the 
fungus after it is introduced into the tissues is effected 
partly by its growth and partly by conveyance by 
means of the lymphatics and leucocytes. Not infre- 
quently a mixed infection with the pyogenic cocci 
occurs in actinomycosis. 
In the earliest stages of its growth the parasite gives 
rise to a small granulation tumor, not unlike that pro- 
duced by the tubercle bacillus, which contains, in addi- 
tion to small round cells, epithelial elements and giant 
cells. After it reaches a certain size there is great pro- 
liferation of the surrounding connective tissue, and the 
growth may, particularly in the jaw, look like, and was 
long mistaken for, osteosarcoma. Finally, suppuration 
oceurs, which, according to Israel, may be produced 
directly by the fungus itself. 
The experimental production of actinomycosis in ani- 
mals has been followed by negative or very unsatisfac- 
tory results. When artificially introduced into the 
tissues the organism is either absorbed or encapsulated. 
If introduced in large quantities multiple nodules are 
apparently formed in some cases, which may suggest 
the production of a general infective process; but on 
closer inspection of these nodules the thread-like . por- 
