ECHINOCOCCUS SCOLICIPARIENS. 195 



cysts, only they are more concealed and more abundantly per- 

 meated by proteinous unorganized substances, by which the walls 

 themselves become thickened, and the mode of secretion of the 

 fluid by which the worm is to be nourished becomes more diffi- 

 cult to understand. The thickness of the walls is not the same 

 in all parts, but in one of Eschricht's cases it was about l'" on 

 the free side looking towards the peritoneum, but nearly 4'" 

 in the interior of the liver. In this envelope, distinctly separate 

 layers or strata could be detected and partly separated ; the in- 

 nermost being ± — 1 millim. in thickness. The innermost stratum 

 is also smooth, like the surface of a serous cavity. It is to be 

 observed also that the enveloping cyst is seldom regularly round, 

 bnt has various excrescences in the part which lies in the paren- 

 chyma of the organ in which the vesicle is imbedded, which there 

 correspond with similar excrescences in the cystic worm living in 

 it. I repeat, what I have already stated once, namely, that such 

 excrescences are not essential ; that we do not know how they 

 are caused, whether by the inhabitant, or by the impulse of 

 organization in the enveloping cyst, which appears to me to 

 be the most probable ; and, lastly, that these excrescences only 

 occur in those individuals of all the cystic worms which live im- 

 bedded in the parenchyma or the cellular tissue of parenchymatous 

 organs, but never in those which live in free, simple cavities of 

 the body — a distinction to which attention has not hitherto been 

 directed, and which, nevertheless, satisfactorily and distinctly 

 explains everything. 



A second vesicular body fits exactly to the inner surface of the 

 innermost layer — this is the true cystic worm, the so-called 

 mother vesicle of the Echinococci, that is, the six-hooked 

 embryo, which, continually increasing, has attained an extra- 

 ordinary size. It is a matter of difficulty in general, at least my 

 attempts for several years have never been successful, to get the 

 cystic worm uninjured out of its cyst, although I have sometimes 

 been able to loosen a greater or less portion of the vesicle from 

 the inner wall, to which, however, it adheres rather firmly. To 

 manage this, I advise that the unopened cyst should be left for 

 some days in spirits, and then that a short cut should be made 

 with blunt-pointed scissors in a thick part of the cyst, and nearly 

 passing through its walls. The margins of the somewhat gaping 

 cuts in the cysts are then seized with two pairs of forceps, with 

 which the walls of the cut are gradually drawn asunder, when the 



