CESOPHAGOSTOMIASIS IN MAN. 47
lie transversly and appear to be more numerous along the posterior wall. They are mostly between the internal muscular submucous coats, and form very prominent bulgings into the cavity. Many small spherical or oval tumours are arranged in rows 2-3 cm. in length. Others infest the plica sigmoidea. They do not appear to com- municate with another.
Several tumours are present measuring 18 by 10 mm., and projecting well into the lumen of the gut, causing manifest obstruction. The walls of the colon in places are extremely thin and occur where large numbers of these tumours infiltrate the muscular coat.
Exteriorly. — Along the anterior and posterior longitu- dinal bands, are dark bluish masses lying between the muscular and peritoneal coats. The walls of the gut are greatly thickened, and the cut surface of the wall shows a hard fibrous-like mass 9-12 mm. thick, which is honey- combed by small oval cavities 3 by 5 mm., in which parts of worms are seen. In many places along the posterior wall it is impossible to make an incision without opening some of these cysts. Many of these cysts appear to have spread towards the mucosa and also external muscular layers, and have formed prominent nodules on both internal and external surfaces of the colon.
On opening a submucous cyst a worm is found lying in a semi-fluid greyish-brown to black-brown mass. The worm may be coiled or twisted on itself or may lie flat and straightened out. The head is usually imbedded in the muscular layer. Sometimes a membranous cast is seen around an immature adult worm, as if it had moulted. Some cysts are seen with ochre-coloured spots on the cyst wall, these are necrotic areas and show " gram " negative bacilli as well as " gram " positive micrococci with
