605 



Literature. In the earlier literature our present interest need 

 be concerned only with the ideas regarding the significance of ami- 

 tosis promulgated by Flemming (1891) and by Ziegler and vom Eath 

 (1891). In brief their observations led them to the conclusion that 

 the direct method of division prevailed in degenerate (pathological) 

 tissue, and in cells highly specialized for the performance of unusual 

 secretory or assimilative functions; that the progeny of a cell which 

 has once divided amitotically cannot divide by mitosis; and that the 

 process leads directly to death. 



Child (1907a) has recorded observations of amitoses in tissues 

 undergoing normal and regulatory growth of representatives of 

 several phyla, including Coelenterata, Plathelminthes, Trematoda, 

 Cestoda, Annulata, Hexapoda and Chordata (Amphioxus, Squalus, 

 Acanthias, Amblystoma, and chick). These "seem to indicate that 

 amitosis is more frequent in connection with rapid nuclear multi- 

 plication" p. 289. Furthermore, "While cell division does not always 

 follow amitotic nuclear division there is no doubt that in many cases 

 it does, and. while degeneration frequently follows amitosis there are 

 undoubtedly many cases in which it does not" p. 289. He inclines 

 to the belief "that mitosis .... may in many cases be characteristic 

 of those regions where nuclear mulitplication is comparatively slow, 

 while regions where the formation of new nuclei is rapid may show 

 only or chiefly amitosis" p. 291. He notes further that "amitosis 

 often occurs where rapid growth is not taking place though it appears 

 usually to be associated with relatively intense activity of some sort" 

 p. 292. In conclusion he attempts to harmonize the apparent con- 

 tradictions that amitoses are the rule in embryonic, specialized, and 

 degenerating tissues by the suggestion that amitosis may be asso- 

 ciated with conditions where the demand for nutritive material 

 exceeds the supply. 



Throughout the development of Moniezia Child (1907 b) reports 

 the regular occurrence of amitosis, both in the somatic tissues and in 

 the germ cells. Eichards (1911) after a reinvestigation of the deve- 

 lopment of this form, concludes "that in the early stages of sex cell 

 development mitosis unquestionably occurs (probably periodically), 

 while amitosis is not evident in my preparation" p. 162. 



According to Dahlgrbn and Kepner (1908) amitotic nuclear 

 divisions occur (without division of cell body) "in nearly all stratified 

 epithelia, especially in the higher vertebrates", p. 40. 



