MITOCHONDRIA IN TISSUE CULTURES 349 



slender processes that are scarcely larger in diameter than a 

 mitochondrium. This rather uniformly scattered arrangement 

 usually occurs during mitosis and here likewise the cell processes 

 may contain mitochondria. The spindle area is usually free 

 from mitochondria (figs. 4, 15, 16, 17). Infrequently in the 

 late anaphase the mitochondria may collect along the plane 

 of division. In elongated cells the mitochondria are usually 

 arranged at either end of the nucleus with their long axis more 

 or less parallel to the long axis of the cell. However, in many 

 of the cells the mitochondria are more numerous about the 

 nucleus or about the central body than towards the periphery 

 of the cell, where they may be scattered or entu-elj^ absent 

 (figs. 4, 5, 12, 17). The central body is an extremely finely 

 granular body at one side of the nucleus and has been so-called 

 by us because the mitochondria frequently radiate around this 

 body and because it is a non-committal term. Usually the idio- 

 zome (or nebenkern, for discussion of correct terminology see 

 Wilson '11) can be seen within this body and occasionally the 

 centrasome can be made out within the idiozome. The central 

 body is more clearly seen in the living cell than in the fixed 

 cell, but in some cells this body cannot be distinguished and the 

 mitochondria appear more or less radially arranged around the 

 nucleus. At times the mitochondria may be confined to one 

 side only of the nucleus, usually the side on which lies the cen- 

 tral body. This radial arrangement about the central body 

 has been described by Eberth (66), Vejdovsky ('07), Meves ('09), 

 Veratti ('09). In some preparations this arrangement is so 

 marked that one cannot but wonder if there is not some definite 

 relationship between the two, and it is not difficult to under- 

 stand why Vejdovsky ('07) believed that the mitochondria were 

 products of the activity of the centrasome. 



The mitochondria, however, are continually altering their posi- 

 tion, not only in relation to the nucleus and central body but 

 also in relation to each other. They seem to be continually 

 emerging from the mass near the nucleus or near the central 

 body and to migrate out towards the periphery. Also those 

 towards the periphery often return to the central mass. There 



THE AMKRICA.N JOURNAL OF ANATOMY, VOL. 17, NO. 3 



