328 T. H. BAST 



Preusse ('95). Ogonia of Hemiptera, 



Pfeffer ('99). In Spirogyra. 



McGregor ('99). In Amphiuma. 



Wasielewski ('03, '04). In root tip of Vicia. 



Patterson ('OS). In pigeon's blastoderm. 



Wieman ('10). In ovaries and testes of Leptinotarsa. 



Jordan ('13). In onion root. 



4. Occurs in regions of rapid growth where the demand for 

 certain foods exceeds the supply. The nucleus in such a condi- 

 tion is not in the proper equilibrium to divide by mitosis and so 

 resorts to the easier method of amitosis. 



Osborn ('04). In food ova of Fasciolaria. 



Child ('07). In both invertebrates and vertebrates. 



Patterson ('08). In pigeon's blastoderm (due to special physiological condi- 

 tions.) 



Wieman ('10). In reproductive cells of Leptinotarsa (change in nutritive 

 supply). 



Glasser ('05). A demand for a greater nuclear surface. 



Jordan ('19). In blood and bone-marrow cells of frog. Lack of nutritive 

 supply due to high degree of specialization. 



5. Amitosis is a purely pathological phenomenon: 



Glasser ('07). Food ova of Fasciolaria. 



Pacaut ('09). In epithelial cells of mammalian cornea. 



6. Amitosis is due to external mechanical pressure: 



Nowikoff ('08, '09, '10) In cartilage, sinew, and bone cells of the mouse embryo. 



7. Amitosis is a nuclear matter only. The cytoplasm does 

 not divide, thus giving rise to a multinuclear cell: 



Heidenhain ("94). 



Karpow ('04). Leucocytes an exception. (His work was on the epidermis of 

 amphibians and epithelium of the urinary bladder of mammals.) 

 Schurhoff ('15). In Ranunculus. 

 Macklin ('16). In the chick embryo. 



8. Amitosis is a normal method of division in vertebrates 

 only: 



Nakahara ('18) makes the following statement : "Amitosis .... is not 

 a method of cell multiplication, nor a sign of degeneration or senescence of cells, 

 but, whenever it occur.s, it seems to indicate an intense activity in the vegetative 

 functions of the cell." 



