284 THE ANATOMY OF CESTODES. 



Virchow first suggested that the calcareous bodies of the Cestodes 

 arose from connective-tissue corpuscles; but although the majority 

 of subsequent observers have supported this opinion — and Schieffer- 

 decker considers that he has even followed the process through all its 

 phases,^ — the cellular origin of these bodies seems now hardly 

 plausible after Harting's ^ beautiful investigations, in which he shows 

 the origin of the various forms occurring so abundantly among the 

 lower animals, and particularly of those which now interest us. The 

 presence of a formed specific organic substratum is by no means 

 necessary, as was formerly believed ; it is sufficient if an amorphous 

 or fluid organic substance be present, with which the carbonate of 

 lime may incorporate itself If the formation occur in ordinary 

 albumen, then calcareous bodies arise of exactly the same form and 

 nature as those of the Cestodes, agreeing with them also in that they 

 exhibit the same clear residue (" Calcoglobulin," Harting) after 

 dissolving away the lime, and they repeat in their individual 

 divergences all the variations above noted. 



There remains, indeed, no reason for connecting the origin of these 

 calcareous bodies with any special cellular structures in the body of 

 the Cestodes. From suitable preparations, and especially from the 

 larval cystic stage at the time of the formation of the head, one can 

 distinctly convince oneself that they arise without the help of ceUs. 

 They originate as small roundish grains, having from the first their 

 peculiar optical and chemical properties, and attain their subsequent 

 size by peripheral growth, i.e., by the deposition of successive sheaths. 

 All the intermediate stages observed between the calcareous bodies 

 and connective tissue cells are, in my opinion, merely concretions, 

 with slightly or unequally distributed lime contents — that is to say, 

 calcareous bodies which contain only a small quantity of inorganic 

 substance, either because it has only been partially deposited, or be- 

 cause the degeneration above referred to has set in. 



The Cuticle. — On its surface the parenchyma of the Cestodes bears 

 a clear unciliated elastic skin, which shows no trace of its elementary 



' Schiefferdecker describes the development o£ the calcareous bodies as follows 

 {loc. cit, p. i70) : — "The doubtful cell first surrounds itself with a membrane. The 

 protoplasm has not its normal appearance ; the granules are further separated ; it looks as 

 though the cell-contents were diluted. The cell becomes more and more invaded by fluid, 

 the protoplasm shrinks round about the nucleus, which then looks like a ball floating in the 

 fluid contents of the cell. The protoplasm seems still further to disappear, — at least only 

 the nucleus remains, and that without its nucleolus. The calcification begins from the 

 nucleus, it works its way out in distinct zones to the periphery, till the calcareous body is 

 finished. I have never seen any connection between the calcareous bodies and the excre- 

 tory canals, nor can I tell why so many connective tissue cells calcify." 



- " Recherohes de morphologie synth^tique, &c.," Naturh. Verh. honinU. ATcad., Deel 

 xiii. : Amsterdam, 1873. _. ... ,. ... „_ 



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