190 Egbert Thompson Young, 



Eeg-arding the question at issue as to the existence of a between- 

 or ground-substance in the parenchyma, I take the side of those 

 who deny it. In both embryonic and adult condition the branching 

 processes of the parenchyma cells may be followed con- 

 tinuously into the finest fibrillae. Any differentiation 

 of cells and ground substance is an untenable view. 



Basement Membrane. During the development of the 

 cuticula, this remains as a narrow zone of undifferentiated paren- 

 chyma strands between the outer ring muscles and the base of the 

 cuticula. In many places it appears to be absent, the muscles 

 abutting directly against the base of the cuticula. It is probable, 

 however, that there are always a few very fine fibrillae separating 

 the two. It is but feebly developed in the yo,ung proglottids of the 

 adult worm, gaining its full development only in the mature pro- 

 glottids. There is thus a separation established here between the 

 outer ring muscles and the cuticula. 



Chalk Bodies. Four different views have been expressed as 

 to the origin of the chalk bodies. By most writers Eixdfleisch 

 (1865), Sommer & Landois (1872), Salensky (1874), Schiefeerdecker 

 (1874), MoNiEz (1881) and others, they have been considered paren- 

 chyma cells metamorphosed by the deposition of calcium carbonate 

 and other salts in the cytoplasm around the nucleus. Salensky 

 (1874), however, thinks that they may occasionally burst the enclosing 

 cell wall and thus come to lie in an inter- cellular space in the 

 parenchyma. A similar tho somewhat modified view is that of 

 Blochmann (1896) and Schneider (1902), who conceived a similar 

 relation to exist in these bodies as exists in fat cells, the calcareous 

 concretion being deposited in the cell, but the nucleus being forced 

 to the periphery and there forming a slight protrusion beyond the 

 outline of the concretion itself (see Blochmann's tab. 1 and tab. 2, 

 fig. 2 and 5); while the third view is that of Leuckart (1879 — 86) 

 who, basing his opinion on the work of Harting^ (1873) in the 

 experimental formation of similar bodies with calcium carbonate and 

 egg albumen, reached the conclusion that they developed as an 

 inter-cellular deposit. Virchow (1857) considered their formation 

 analogous to that of bone by the deposition of CaCOg in a connective 

 tissue stroma. The exact relation between the cell and the calca- 

 reous concretion is not made clear by him however. 



