MITOSIS AND AMITOSIS. 397 



but secondarily with several other animal forms ranging all the 

 way from coelenterates to birds. 



Among other recent writers who have maintained a similar 

 view are Hargitt (1904, 1911) on amitosis in the cleavage of the 

 eggs of coelenterates, Patterson (1908) in blastoderm cells of the 

 pigeon, Glaser (1908) in embryonic cells of Fasciolaria, Jordan 

 (1908) in spermatogonial divisions of Aplopus, Nathansohn 

 (1900) in Spirogyra, Wasielewski (1902, 1903) in the root tips 

 of Vicia, Gurwitsch (1905) in the blastomeres of Triton, Maximow 

 (1908) in embryonic tissues of the rabbit, Jorgensen (1908) in 

 the oogenesis of Nephelis, Moroff (1909) in the eggs of copepods, 

 Knoche (1910) in the insect ovary, Nowikoff (1910) in bone 

 and sinew cells of the young mouse, and Foot and Strobell 

 (1911) in the ovary of Protenor all of whom hold that amitosis 

 may occur as a normal process in germinal and embryonic cells. 

 Several of the authors named as well as R. Hertwig (1898), 

 Lang (1901), Calkins (1901), Herbst (1909), Godlewski (1909) 

 and Konopacki (1911) hold that there is no principal distinction 

 between mitosis and amitosis and that they may both occur 

 without interfering with normal processes of differentiation. 



On the other hand, this view is contested by Boveri (1907) 

 and Strasburger (1908) on general grounds and is not confirmed 

 by the experiments of Hacker (1900) and Schiller (1909) on 

 Cyclops eggs subjected to ether, nor by the experiments of 

 Nemec (1903) who repeated the work of Wasielewski on the 

 root tips of Vicia subjected to chloral hydrate and Beached the 

 conclusion that the supposed amitoses are really modified mitoses. 

 Richards (1909, 1911) and Harmon (1913) carefully and labori- 

 ously repeated Child's work on cestodes and found no evidence 

 of amitosis in germ cells or cleavage cells, while on the other 

 hand there was abundant evidence of mitosis. Child (1911) 

 has reexamined the question and reaffirms in the main his 

 former opinion, and this has been confirmed by Young (1913), 

 whose general conclusions, however, are so reactionary and even 

 revolutionary that they cannot be accepted without further 

 confirmation. 



Boveri (1907) has said that if Child would establish his con- 

 tention he must prove (i) that the binucleate condition which 



