CELL DIVISION IN T.ENIA. 



3 2I 



The meaning of amitosis in the parenchyma is of quite different 

 import from that in specialized tissues. Parenchyma is a tissue 

 from which others are derived ; it is neither highly specialized, 

 degenerating or pathological. The occurrence of amitosis here, 

 therefore, would not be in line with the old theory. 



Concerning the nature of parenchyma there has been much 



H 18 



FIG. 17. Second oocyte in which mitosis is nearly complete, yet no sign oi cell 

 division. The daughter nuclei are being constricted apart and the chromatin masses 

 are disintegrating. Zwischenkorper present. 



FIG. 18. Outline drawing of Fig. 17. It gives the appearance of an "endogen- 

 ous" division by amitosis. Fig. 17 shows that appearance to be entirely superficial. 



controversy, but it is beyond the scope of this paper to enter into 

 a discussion of the question or of the literature regarding it. In 

 connection with an account of the method of cell division, how- 

 ever, a few observations concerning it cannot be avoided. The 

 older view held by Leuckart and his followers was that the paren- 

 chyma develops from rounded and polyhedral cells, the latter 

 sending out processes which interlace about the former. Moniez 

 and his followers offered an opposed view. Opinion has by no 

 means become settled even now. Child speaks "of the paren- 

 chyma cells if the syncytium which composes the parenchyma 

 can properly be said to be composed of cells." 



Parenchyma consists of calcareous bodies and irregularly 

 shaped cells lying in a mass of material which seems to be inter- 

 cellular. Of these, the first do not enter into the question under 

 consideration, and the intercellular matter only figures as a 

 ground substance in which the cells are imbedded. The cells 

 vary in shape from elliptical and spindle-shaped to an irregular 

 form with many protoplasmic processes. In size there is also 

 much variation, due, largely, to the variation in the amount of the 



