402 THE AMERICAN NATURALIST [Vol.LII 



differentiation. An hyperplasia with differentiation into 

 specific tissue-cells may be called texto-typic in contra- 

 distinction to that without differentiation, which may be 



termed eytotypic. This occurs before and after mi- 

 gration. 



According to writers on the subject of cancer the prin- 

 cipal criterion for the denotation of a condition by this 

 term consists of the destructive migration of tissue-cells. 

 Such neoplasms have been often considered to be direct 

 derivatives of tissue-cells, because their cells sometimes 

 resemble those of specific tissues of organs from which 

 they have arisen. As a matter of fact the malignant 

 neoplastic cells (neocytes) do sometimes resemble the 



