STUDIES OF AMITOSIS 501 



bladder of mammals, and many other tissues, suggested an idea 

 that the initiative constriction in amitotically dividing nuclei 

 is due to the physical property of nucleus and the osmotic phe- 

 nomenon. He observed that in places where amitosis is occur- 

 ring very frequently, the multiplication of cells is not effected, 

 but that of nuclei is. The direct division of the amphibian leuco- 

 cyte is the only case in which the nuclear division is followed by 

 cytoplasmic division. Examining fresh material under the mi- 

 croscope, he noticed that leucocytes easily adhere to the cover 

 glass: this makes the free locomotion of leucocytes difficult, 

 and hence come an expansion and finally a division of the leuco- 

 cyte in a mechanical way. As far as his data indicate, the 

 normal amitosis always produces multinucleate cells, and so it 

 cannot be regarded as a method of cell multiplication. 



Gurwitsch ('04) said, in his review of the subject, that ami- 

 tosis may be of more biological importance than was supposed by 

 Flemming and others, and that the possibility of one method 

 taking place of the other in nuclear division should also be 

 admitted. 



Glaser ('05) observed in Fasciolaria that amitosis is associated 

 with a high vegetative activity and stated that it may contrib- 

 ute to such function, bringing about the great increase of 

 nuclear surface. 



Child ('07a), working out a number of cases of amitosis in 

 various animals, both vertebrates and invertebrates, maintained 

 the view that this kind of nuclear division is associated with con- 

 ditions where the demand for material or perhaps for certain 

 substances exceeds the supply. He believes that amitosis oc- 

 curs in regions of rapid growth as well as in regions where active 

 processes of secretion or reserve formation are concerned, and 

 said ''since orthodromic processes pushed to the extreme must 

 always result in total destruction of the original substances, it" 

 is not strange that degeneration frequently follows amitosis, 

 but there is no reason for believing that it must always follow." 

 He failed in reconciling his theory of amitosis and the chromo- 

 some-theory, which he regards as very improbable as a universal 

 hypothesis. 



