68 
of the cyst comprise large mononuclears, some polymorphonuclears, a few large 
hyaline cells and some pigment-containing cells, these latter are situated at the 
periphery of the cyst. The red blood cells are nearly all degenerated. A 
longitudinal section of a worm is present and in the intestine several polymorpho- 
nuclears, mononuclears and a few degenerated red blood cells are seen. The walls of 
the cyst have a well-marked necrotic lining, in which are a few polymorphonuclear 
leucocytes. The connective tissue of walls is infiltrated by large mononucleated 
cells, and a considerable number of eosinophiles. Pigmented cells are seen in rows, 
directed towards the subperitoneum. The intermuscular space contains very 
distended blood vessels. 
Sub-peritoneal cyst; leech-like tumour; longitudinal section. 
Serial sections show that the cyst has developed in the loose areolar tissue of 
the subperitoneal space and that the fibres of the external muscular coat are not 
involved nor atrophied. The tumour has everted the peritoneum and has so 
developed that the sides and ends bulge and overhang like a mushroom. The cavitv 
of the cyst measures over 8 mm. in length. The walls of the tumour are formed of 
thickened connective tissue which is greatly hypertrophied at the two ends. The 
cyst is not partitioned and the cavity is filled from end to end with many degenerated 
cells, some red cells, mononuclear leucocytes, and two sections of a worm, a 
transverse and a longitudinal one. The thickened evst walls, especially the two end 
and basal walls, are infiltrated with leucicytes. 
, Cn< ^ t * ie c y st ’ * s a w ell-defined necrotic area which occupies the 
whole thickness of the internal muscular coat; the submucosa and internal fibres 
the external muscular coat in the vicinity of this necrosis are infiltrated bv 
large mononuclear cells. 
n„rlH ym cf m the , cavit >' are ma sses staining lightly with eosin and possessing no 
of i T f ,on S ated bands which appear to consist of degenerated fibres 
moulT of J Si map J nification - the y resemble the cuticular remains from the 
Tnsfde U rh V ° rm - rCd Ce,,S afe Rouped aroiind the worm, but none is seen 
sides of theT^ir n0 ^rf- arS and ,arge P° ] y.Sonal cells are most numerous at the 
are infiltrated h I 3Sues oi tbe retaining walls immediately around the evst 
are vefy numerous onl I** !”° nonu . clea ” and small lymphocytes; eosinophiles 
and fewer eosinonh’il ° ' V 3 t ' v ar " e Pigmented cells are found. Less infiltration 
the cys^showTxtpntiiTO ^ OUter P ar ‘ of the walls. The end walls of 
but, further in the tissued Cm ? S with very little infiltration in the outer layers, 
infiltrated by a’few mononuclears which extend^ih muscu,ar C ° a * iS 
many ^arge^niononuclear^^^ew' 11 ^ 0 ^^ 1 ^ ^ I m^s<^?M U ^at S ^is C fiilled with 
httle pigment. Outside the necroti^a^^a**^ N£ I,ne ceI,s containing a 
cells and large mononucleated rr-iic u- , intense infiltration of small round 
involve the intermuscular space and the 1,ch extend lhrou g h the entire coat and 
coat ; on the other side they penetrate ih C " tl S uous fibr es of the external muscular 
great, and does not extend to thn - e submucosa » where the infiltration is not so 
ex ter naf muscu 1 ai -6 coat d^ex t ended'to *th™^” b ^g u n in the outer fibres of the 
number of pigmented cells and free &Ve ™ ore red blood cells and a considerable 
seen. The infiltration of the walls i« if™ 6 ' 14 g ranules : very few eosinophiles are 
present. No masses resembling the and more sma11 round cells are 
are to be found. A small haemnrrVi U ar remains of tbe moult of the parasite 
istending the space and lifting ud the < j yS * ll6S ad i acent . in the submucosa, 
muscular coat adjoining the cyst lire Lmewhlt"! T*® 1 * he fibres of the internal 
m tration of this layer with mononnH & r ° pbied > and there is considerable 
eosinophiles and large giant cells. pi ^ mented a few 
of the cyst are composed of masses 
