Parasites of the Liver. 339 



CYSTICERCUS PISIFORMIS IN THE LIVER. 



This parasite is the cystic or larval stage of the taenia serrata of 

 the dog. The rabbit, having taken in with food or water, one or 

 more ripe .segments of the taenia, or some of the eggs furnished 

 by these, hatches out the eggs in its stomach or intestine, and the 

 six-hooked ovoid embryos boring their way through the intesti- 

 nal walls and those of the portal vein reach the liver, where they 

 cause emboli and live in the clots which obstruct the vein, as 

 already described of the embryos of the C. Tenuicollis. By the 

 second day after the inge.stion of the eggs the presence of the em- 

 bryos in the liver is manifested by fine, tortuous, red lines and 

 very small white globular bodies at some part of their course. By 

 the fifth day the projecting globular body has acquired the size 

 of a hemp-seed, is ea.sily picked out without disturbing the 

 hepatic tissue, and shows a thick wall enclosing.a clear refrangent 

 corpuscle. Laulanie has .shown that these lesions consist in the 

 obstruction and obliteration of the portal venous branch by the 

 clot in which the embryo is embedded. The blocking of the 

 veins in animals that survive, entails impaired function and 

 cirrhosis of that portion of the liver which the blocked vein nor- 

 mally supplies with blood. The thickened connective tissue is 

 remarkable for the abundance of dilated capillary blood vessels 

 and for the presence of giant cells (Plana). The giant cells often 

 enclose a minute central clot of blood (Cadeac). They are also 

 often invaded by bacteria (Neumann). In the .same way the 

 blood clot surrounding the embryo is colonized by bacteria 

 brought by the parasite from the intestine, and the debris of a 

 dead embryo may be surrounded by a limited formation of pus. 



The surviving embryo, at first one millimetre in length, grows 

 rapidly and on the twenty-.second day may measure a centimetre 

 long by a millimetre broad. It now becomes constricted in the 

 centre and gradually divides in two, one of which is disintegrated 

 and absorbed, while the other develops a globular head and forms 

 the cysticercus (Moniez). About a month from its ingestion the 

 cysticercus reaches the surface of the liver, where it may remain 

 attached and hanging into the peritoneal cavity, or it may become 

 detached and float off in the abdomen to form a new attachment 

 to any part of the peritoneum or to any abdominal viscus. 



Symptoms. As in the case of cysticercus tenuicollis, symptoms 



