EFFECTS PRODUCED BY CITTIXG PARAMKCIUM 



CELLS. 



GARY N. CALKINS. 



CONTENTS. , A ,., 



M.i l. -rial ami Mrthods 37 



1 allies of Experiments 40 



Analyses of Tables and Experiments 47 



Analysis of Table 1 47 



Analysis of Table II 48 



Analysis of Table III 51 



Analysis of Table IV 52 



Monster Forms 53 



General 59 



Summary 65 



Papers Cited 67 



Description of Plates 68 



In a previous paper on Urouychia I have shown that the 

 power of regeneration in a hypotrichous ciliate is a factor of cell 

 age, increasing as the cell grows older after division, until a 

 maximum power is attained just prior to cell division. In the 

 present paper I desire to describe the results obtained by similar 

 methods of experimentation on a much more difficult subject, 

 the holotrichous ciliate Paranicciuni. Here in forms from 

 ordinary cultures, the power of regeneration is very poorly de- 

 veloped and the nuclear apparatus is more concentrated. Similar 

 experiments on Parameciitm have often been attempted, but 

 tin- difficulties in technique are so great that, with the exception 

 of Balbiani's beautiful work in 1893, little or no extensive work 

 has been done. The endeavor to ascertain what happens in a 

 cell in which the power of regeneration is slight and when the 

 physico-chemical equilibrium is suddenly disturbed is a problem 

 \\ ell \\ orth the patience and repeated failures necessary in getting 

 I he small percentage of success, and the results obtained at 

 intervals during the last three years are. here- brought to.m '. hei 

 for the first time. In a subsequent paper I shall publish my 

 results with anoihrr race of Paramecium cuudatnm on regenera- 

 tion in relation to <vll division. 



36 



