288 A CTINOM YCOSIS. 



the paths of entrance being very various. In many cases 

 the entrance takes place in the region of the mouth 

 probably around a decayed tooth by the crypts of the 

 tonsil, or by some abrasion. Swelling and suppuration 

 may then follow in the vicinity and may spread in various 

 directions. The periosteum of the jaw or the vertebrae may 

 thus become affected, caries or necrosis resulting, or the 

 pus may spread deeply in the tissues of the neck, and may 

 even pass into the mediastinum. Occasionally the parasite 

 may enter the tissues from the oesophagus, and in a 

 considerable number of cases the primary lesion is in 

 some part of the intestine, generally of the large intestine. 

 The parasite penetrates the wall of the bowel, and may 

 be found deeply between the coats, surrounded by puru- 

 lent material. Ulceration, and sometimes a considerable 

 amount of necrosis may follow. Thence it may spread to 

 the peritoneum or to the extraperitoneal tissue, the retro- 

 caecal connective tissue and that around the rectum being 

 not uncommonly seats of suppuration produced in this 

 way. A peculiar affection of the intestine has been 

 described, in which slightly raised plaques are found both 

 in the large and small intestines, these plaques being com- 

 posed almost exclusively of masses of the actinomyces 

 along with epithelial cells. This, however, is a very rare 

 condition. The path of entrance may also be by the 

 respiratory passages, the primary lesion being pulmonary 

 or peribronchial ; extensive suppuration in the lungs may 

 result. Infection may also occur by the skin surface, and 

 lastly, by the female genital tract, as in a case recorded by 

 Grainger Stewart and Muir, in which both ovaries and 

 both Fallopian tubes were affected. 



When the parasite has invaded the tissues by any of 

 these channels, secondary or " metastatic " abscesses may 

 occur in internal organs. The liver is the organ most 

 frequently affected, though abscesses may occur in the 

 lungs, brain, kidneys, etc. In such cases the spread takes 

 place by the blood stream, and it is possible that leucocytes 

 may be the carriers of the infection, as it is not uncommon 



