ECHINOCOCCUS ALTEICIPARIENS. 223 



When the vesicles passed have an opening, the little scolices 

 slip out only too easily, and if we do not find the structures just 

 described, we do not know whether we have not before us a 

 sterile colony or acephalocyst. I will answer for it, and every 

 one who has experience will confirm this, that even where the 

 hooks are wanting, the little Echinococci are easily recognisable 

 by the above form. In this way we may recognise the Echino- 

 cocci of the kidneys when the vesicles pass out with the urine 

 (J. Miiller, Frerichs, myself, and others) ; v/hen they pass through 

 the mouth, by coughing, from the thoracic viscera, especially the 

 lungs, although the colony may at first have its station in the 

 pleura j 1 and the colonies of the liver and spleen when the vesicles 

 are seen to pass from the mouth during vomiting, or from the 

 anus. But even here it is always possible that we may be in 

 error as to the position of the colony, and we only acquire 

 a certainty as to the existence of Echinococci in the body. Thus 

 no doubt Echinococci of the ovaria may perforate towards the 

 anus, and also through the vagina or the bladder, nay, even 

 Echinococci of the liver may pass through the bladder when they 

 are of enormous size. In the examination of such cases we 

 must carefully consider whether we can discover the original seat 

 of the swelling which was formed by the colony, thence trace its 

 growth further by the diminution of the swelling existing before 

 the bursting, and obtain a further foundation for our opinion by 

 the comparison of the former and actual conditions. Every 

 thinking practitioner will be able to form the differential 

 diagnosis for himself easily with the assistance of auscultation, 

 and especially of percussion, and combination of auscultation and 

 percussion. We shall only indicate this in a superficial manner. 

 Thus, after the perforation of a cyst has taken place in the direc- 

 tion of the intestine, it may easily happen that, where shortly 

 before there was a circumscribed swelling which gave dull tones 

 on percussion, a very distinct air-tone may be suddenly observed 

 in consequence of the entrance of the gases of the intestines, 

 just as we often see these phenomena occur in ovarian tumour, 



1 A very credible teacher of surgery mentioned a case to me in which a gelatinous 

 vesicle was thrown up by a patient whilst coughing, and fell into the spittoon, when a 

 cat came and ate up this gelatinous body. This could only have been the daughter- 

 vesicle of an Echinococcus or an acephalocyst. However, the story of the cat is no 

 longer to be regarded as a fable or an absolute impossibility, since our experiments in 

 feeding have shown how greedy dogs and cats arc after cystic worms. 



