HYDATIDS IN THE ABDOMINAL VISCERA. 157 



gradually, and is unattended by much pain, by fever, 

 or by jaundice, can scarcely be attributed to any 

 other cause than hydatids. When the cyst is deve- 

 loped near the upper border of the Hver, it pushes 

 up the diaphragm, and may be distinguished from 

 pleuritic effusion by the signs which have been 

 already described. 



An hydatid tumour of the liver is readily dis- 

 tinguishable from an abscess in the same situation, as 

 the latter seldom acquires a large volume without 

 being preceded or accompanied by pain or fever, and 

 it may also be distinguished from a cancerous tumour 

 of the liver by its larger size, and by its forming a 

 globular, smooth swelling, whilst in cancer the en- 

 largement usually presents a nodulated character, 

 besides which the various symptoms of cancerous 

 cachexia will generally complete the diagnosis. 



Distension of the gall-bladder may more probably 

 be mistaken for an hydatid cyst ; it is, in fact, 

 globular, smooth, and compressible, but it is con- 

 stantly, and almost from the commencement of the 

 affection, accompanied by great yellowness of the 

 skin, and by acute pain, and the hydatid-trembling 

 can never be detected in it. 



Hydatids of the Kver may also be mistaken for 

 aneurism of the aorta, which, like an hydatid cyst, is 

 globular, and painless upon pressure, and does not 

 give rise to jaundice, or to serous effusion into the 

 peritoneum, or to disordered digestion, or to impedi- 

 ment to the respiration, at least not until it has 

 acquired considerable dimensions ; but the very dis- 

 tinct pulsations, and the bellows -sound which is 

 perceptible upon applying the stethoscope at the 



