THE OCCURRENCE OF AMITOSIS IN MONIEZIA. 



C. M. CHILD. 



In a recent paper, " On the Method of Cell Division in Tcenia,'" 

 by A. Richards/ the author records his failure to find amitotic 

 division in Tcenia and suggests on the basis of his results that my 

 conclusions concerning amitosis in Moniezia^ are due to errors of 

 observation. 



The appearance of this paper makes it necessary for me, in 

 defence of my observations, to emphasize certain features of my 

 own work, to which Richards has apparently not given adequate 

 consideration, to add a few observations not included or only 

 briefly referred to in my earlier papers and finally to subject his 

 attempts at interpretation to critical analysis. 



In the first place, it might seem that the reading of my state- 

 ment concerning methods of fixation and precautions employed 

 (I., pp. 89-93) would suggest to anyone that I had exercised at 

 least some degree of care in order to avoid errors of observation 

 of so gross a nature as the mistaking of a mass of " Nebendotter " 

 for a nucleus. As I stated, fresh material was fixed by the most 

 various methods during each of four successive years, and a large 

 part of my time during this period was devoted to the study of 

 the preparations, from which hundreds of camera drawings were 

 made. The work was begun simply because the apparent absence 

 of mitosis in certain regions of growth interested me, and I ex- 

 pected to find either some unusual type of mitosis or else short 

 recurrent periods of mitosis. What I did find, however, led me to 

 exercise the utmost care and to go over the ground repeatedly 

 even after I had published my preliminary paper in 1904.^ Dur- 

 ing the whole period of my work I was constantly searching for 



iBioL. Bull., XVII., 4, 1909. 



2Child, "Studies on the Relationbetween Amitosis and Mitosis," I., Biol. Bull., 

 XII., 2, 1907 ; II., ibid., 3-4 ; III., ibid., XIII., 3, 1907 ; IV. and V., ibid., 4. 

 In later references to these papers in the text they will be designated simply by the 

 Roman numerals I.-V. 



*" Amitosis in Moniezia,^^ Anat. Am., XXV., 22; 1904. 



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