200 ON THE ANATOMY OF ECHINOCOCCUS VETERINORUM 



Behind the circlet of hooks, the shape of a transverse section of the 

 body is quadrilateral, and at each of the four corners a large rounded 

 disc with a more or less flat surface is to be seen, — the sucker. In 

 structure, when unaltered, the suckers appear to be homogeneous, 

 with granules and two or three of the peculiar corpuscles to be de- 

 scribed immediately, imbedded in their substance. Under the action 

 of acetic acid, however, a radiated fibrillation frequently became 

 visible. 



Scattered through the substance of the Ecliinococcus, and giving 

 it a very peculiar dotted appearance under a low power, a number of 

 oval, strongly refracting corpuscles may be observed. They are very 

 uniform in size, and have a long diameter of about -j-jV th of an 

 inch. They are what have been called the calcareous corpuscles of 

 the Echinococcus ; — inasmuch, as in the Cysticerci and other cystic 

 worms they have been observed to be converted into carbonate of 

 lime ; but I believe that this is entirely a result of that peculiar de- 

 generation to which the cystic Entozoa are so liable, and that, in the 

 young and normal adult state, these peculiar corpuscles (which are 

 found in all the Cestoidea and Cystica^ are never calcareous, but arc 

 composed of an albuminous substance. 



The mistake has arisen, I think, from two causes. In the first 

 place, in old cystic worms these corpuscles arc frequently converted 

 into a calcareous substance, although they retain their transparency 

 and strongly refracting powers ; and secondly, because when acid is 

 added to a number of Echiiiococci, gas is very commonly developed 

 from calcareous substances contained either in them or in the fluid 

 in which they swim ; at the same time the action of the acid rapidly 

 causes the corpuscles to become clear vesicles, so that nothing seems 

 more natural than to connect the one circumstance with the other. 



Having paid great attention to the process, however, I can, 

 decidedly affirm — 



1. That acetic acid dissolves out the contents of the corpuscles in 

 young and fresh Echinococci, without the least evolution of gas from 

 them ; and that the same assertion holds good of the corresponding 

 corpuscles contained in the spirit specimens of TcEnia and Botlirio- 

 ceplialus which I have examined. 



2. That caustic ammonia produces little cavities and sometimes a 

 concentric lamination in these bodies. 



And, 3rdly, that in a spirit specimen of an Ecliinococcus from the 

 Panther (which Dr. Hyde Salter kindly lent me), the corpuscles 

 appeared vesicular without the action of any reagent. 



It may be said then, that the peculiar strongly refracting cor- 



