40 NORMAL HISTOLOGY, 



mode of cell-division appears to be an exactly equal partition of 

 all parts of the chromoplasm between the young cells. Whether 

 the amount of cytoplasm given to the daughter-cells is the same 

 or different, the division of the chromoplasm is exactly equal, not 

 only in its whole bulk, but each chromosome, which appears to be 

 the morphological unit of the chromoplasm, is split into exactly 

 equivalent halves, one of which is contributed to the formation of 

 each daughter-nucleus. It is for this reason that the chromoplasm 

 is looked upon as the carrier of hereditary peculiarities. 



Fig. 17. Fig. 18. 



Fig. 17.— Dispirem. In this case the polar bodies have not divided (compare Fig. 16). 



Fig. 18.— Daughter-nuclei which have nearly reached their full development. Centrosomes 



present in the cytoplasm. 

 In these figures the structure of the cytoplasm is not given. 



After the formation of the daughter-nuclei, the centrosome 

 usually passes from it into the cytoplasm. It may divide earlier 

 than has been described, the division taking place while it exists 

 as the polar body, or even earlier (Fig. 16). 



A cell nearly always divides to form two new cells, but some- 

 time- three or more cells may be produced, the chromosomes being 

 distributed among them (Fig. 19). Such cases are probably 

 always morbid, and the resulting cells are not wholly the equiv- 

 alents of the parent cell. 



It occasionally happens that the cytoplasm fails to divide after 

 the formation of the daughter-nuclei, and cells with two or more 

 nuclei result. When the nuclei continue to multiply and the 

 cytoplasm increases in amount, but does not suffer division, large 

 multinucleated cells are produced, which have been called "giant- 

 cells." They occur normally in the marrow of bone and are pro- 

 duced in many of the inflammatory processes. 



The direct or amitotic method of cell-division is inaugurated by 



