AMITOSIS IN BONE CELLS 



335 



of this type in smooth muscle cells of the human uterus (text 

 fig. 2, 8b, h, c, and d). Such cases are also quite common among 

 lymphocytes. 1 



CELL FRAGMENTATION 



There are cases of unequal division which in reality are not 

 true cell division, but only types of cell fragmentation (text 

 fig. 1, d). Nowikoff found such cases in tendon and bone cells. 

 He decided that such division was due to external pressure. 



Text fig. 2 Camera-lucida drawings of smooth muscle cells from a pregnant 

 human uterus, a, b, c and d show different forms of the third type of amitotic 

 division. Original drawings were made on the scale of X 1200, but were reduced 

 in reproduction to f of the original. 



Maximow found them in mesenchymal tissue. The large masses 

 of bone-cell protoplasm with or without nuclear fragments 

 which I have found in bone (fig. 2, also fig. 4 of previous paper) 

 belong to this type. 



'Dr. C. H. Bunting, of the Pathological Laboratory of the University of Wis- 

 consin, called my attention to this type of division among lymphocytes. 



