author's abstract of this paper issued 

 BT the bibliographic service, august 5 



VARIOUS TYPES OF AMITOSIS IN BONE CELLS 



T. H. BAST 



Anatomical Laboratory, University of Wisconsin 



TWO TEXT FIGURES AND ONE PLATE (TWELVE FIGURES) 



INTRODUCTION 



After seeing some of my preparations, Dr. H. E. Jordan suggest- 

 ed to me that a more extended study might add something to 

 our knowledge of amitosis in the growth and repair of the hving 

 mechanism. ITpon careful examination of the preparations of 

 bone cells, many stages of nuclear and cells division were noted. 

 These observations showed that amitosis was the only method 

 of division present. Other preparations were made from various 

 ages of bone and from various animals. In these preparations 

 all stages of amitotic division were present, but not a single 

 mitotic figure could be found. In the light of the recent discus- 

 sions on the prevalency, cause, and significance of amitosis, 

 these observations are very suggestive, especially since the various 

 stages of division are so numerous and clear. Of greater import, 

 however, for our knowledge of cell division is the observation 

 that in the multiplication of bone cells two types of amitosis 

 occur, and that these types are not only due to the difference 

 in the form of the dividing nuclei, but that the form of division 

 is also determined by the activity and position of the centrosomes. 



MATERIAL AND TECHNIQUE 



The parietal bones of new born to three-weeks-old rats and 

 the nasal bones, especially the ethmoid of the dog and rabbit, 

 served as material for this study. Small pieces of bone are 

 fixed in 95 per cent alcohol. The technique for their further 

 preparation is the same as that described in my previous paper. 



321 



the AMERICAN JOURNAL OF ANATOMY, VOL. 29, NO. 3 



