THE ASCAEIS LUMBRICOIDES. 95 



Lumbrici may occasionally pass out of the intes- 

 tine into the pancreatic, or the biliary ducts ; it is 

 probable that in such cases the duct is more dilated 

 than usual, either in consequence of abnormal en- 

 largement, or else through some temporary cause, 

 such as the passage of a gall-stone down the bihary 

 ducts. 



Lumbrici which have entered the biliary passages 

 have been observed to be either contained partly 

 within the ductus choledochus and partly within the 

 intestine, or completely within the ductus communis 

 choledochus, or the gall-bladder, or in the liver, where 

 considerable changes of structure may have taken 

 place owing to the irritation produced by the worm 

 in that situation. 



The presence of an ascaris lumbricoides in the 

 bUiary passages gives rise to various lesions ; it 

 occasions or it maintains dilatation, and sometimes 

 rupture, of the duct which it has invaded ; the 

 dilatation may be either general, or else partial and 

 limited to the portion of the duct which is occupied 

 by the worm, which then appears as if it were con- 

 tained in a special pouch. Neither the rupture of 

 the duct nor the injury which is done to its internal 

 surface, are attributable (as some say) to the suction 

 of the lumbricus, but are due rather to the impedi- 

 ment which is offered to the passage of the bile, or 

 else to the merely mechanical irritation which is 

 produced by the presence of the worm, and is similar 

 to that which would be caused by any other foreign 

 body in the same situation. 



Inflammation and suppuration usually occur when 

 the worms have penetrated deeply into the bihary 



