222 ANIMAL PAEASITES. 



speak of the origination of the original vesicles from a single 

 germ, and all other isolated vesicles must certainly be accounted 

 for by an equal number of separate germs. Whether all the 

 Echinococcus-vesicles of the liver referred to were produced from 

 a single germ, is therefore questionable embryos may, pro- 

 bably, have immigrated directly into many places. With regard 

 to the colour of the folded Echinococcus- vesicles (gelatinous 

 masses of the alveolar colloid) we have still to mention that many 

 of the membranes of the vesicles presented so white, fresh, and 

 delicate an appearance, that it might be supposed that they and 

 their germs were still alive. If I am not mistaken, I have once 

 bred Tania Echinococcus scolicipariens from a folded, gelatinous 

 mass, beset with scolices, taken from the liver of a pig. How- 

 ever, Virchow's assumptions, as far as they refer to the produc- 

 tion of acephalocysts, agree exactly with mine. 



Symptomatology. The general and partial functional derange- 

 ments, the objective phenomena, and the subjective sensations 

 vary according as the position of the Echinococcus is more super- 

 ficial or the reverse, according to the organ which it has selected 

 for its dwelling-place, according to the size which it has attained, 

 the pressure which it exerts, arid the vicinity of large nervous or 

 vascular trunks. The phenomena produced by it agree exactly 

 with those caused by other equally large tumours in similar 

 situations, upon which every text-book of special pathology 

 and therapeutics, or surgery, will furnish information. In 

 order to avoid too great prolixity, I pass over the symptoma- 

 tology, and shall only mention that when the organ inhabited 

 is one containing air, auscultation and percussion furnish 

 important information, which we shall refer to in the diag- 

 nosis. 



Diagnosis. The most certain evidence of the presence of a 

 colony of Echinococcus in the body of a patient is the pas- 

 sage of the gelatinous vesicles already described from open 

 cavities of the body, which occurs after the bursting of such a 

 colony, or the similar passage of such vesicles from the punctures 

 or incisions made into tumours. At the same time, hoivever, the 

 little scolices of the Echinococcus must be found in the vesicles ; 

 part of these retain their hooks, whilst others want them, and when 

 their sucking-discs are indistinct they resemble (at least I know no 

 better comparison) very small dolls inclosed in cradles } or have 

 the form of little swaddled children. 



