262 ACTINOMYCOSIS 
can be found. If the pus is spread in a thin layer on a smooth surface 
granules composed of the organism can often be seen with the unaided 
eye. These pus cavities are usually connected with each other by 
small sinuses but sometimes they are separated by bands of fibrous 
tissue. 
If the disease is in the bone as it is when the specific organism gains 
entrance and begins to grow in the interior of the jaw, the bone tissue 
about the organism becomes in places disintegrated and absorbed and 
pockets are formed containing the granules. While the interior of the 
Fic. 58. ACTINOMYCOTIC NODULES IN THE NASAL CAVITY OF A SIX YEAR OLD Cow. 
(AFTER JOEST). 
bone is being broken down and absorbed by the action of the actino- 
mycotic growth within, its diameter is being increased by the invasion 
and deposition of new material until it may become several times its 
normal size. 
The lesions spread in most cases by gradual invasion of the tissues 
surrounding the infected point. At the seat of infection, minute, 
inflammatory points appear, which extend at their periphery and 
unite to form larger areas of diseased tissue. These masses tend to 
extend in one direction and to heal in another, leaving behind bands 
of cicatricial tissue. The process usually differs widely from that of a 
simple inflammation. In its progress the disease shows no preference 
for structures but invades one tissue after another so that all may be 
involved alike. 
