miscellaneous: stimuli underlying tumor-formation 515 



volume of oxygen offered to such a cell (I am not here thinking 

 of anaerobes) is reduced by the abstraction either of water or of 

 air, it is plain that the only way the cell has of compensating 

 for this reduction of an absolutely necessary substance is by 

 cell-division, that is by increasing the area of its oxygen-absorb- 

 ing surface, or to put it in other words, by increased respiration 

 through the development of a hyperplasia.^ If the amount of 

 oxygen offered to the tissues is much below the amount required, 

 then the hyperplasia will be fine-celled and active, if it is only a 

 little below the needs of the tissues, the hyperplasia will be 

 coarse-celled and slow-growing. All the evidence we have, 

 enzymic and other, points to increased respiration in tumors of 

 all kinds, and their feeble vascularization and correspondingly 

 slow and uncontrolled circulation leads to just the stasis neces- 

 sary to produce more or less oxygen-hunger. I do not mean 

 that there is complete absence of oxygen because in ordinary 

 plants and animals that would mean prompt asphyxiation and 

 death of tissues. Asphyxiation also occurs often in tumors 

 but it is an end term that need not concern us here. What I 

 mean is just sufficient reduction of the normal supply of oxygen 

 to bring about cell-division for compensatory purposes, i.e., to 

 afford a larger oxygen absorbing surface. 



Two factors, at least, may be supposed to enter into this 

 semi-asphyxiation hyperplasia under obturated lenticels: (1) 

 oxygen-hunger, the cells being no longer bathed freely by air or 

 by aerated water in movement toward the lenticel ; (2) increased 

 acidity of the cell- ap (from incomplete combustion of carbon 

 compounds , leading to more or less paralysis of the proto- 

 plasmic membrane (the hyaloplasm which governs intake and 

 outflow) with correspondingly increased cell-permeability, allow- 

 ing water to escape, and water, sugar and other food-stuffs to 

 be brought back into the cells in increased quantities from 



1 The reason the bacterial cell accomplishes work out of all proportion to its 

 size is just this, that its oxygen absorbing surface is enormously greater in propor- 

 tion to volume of protoplasm than that of any other known organism. The surface 

 of the rods in a cubic centimeter of bacterial slime, such as we frequently obtain 

 in a test tube on our solid media and observe in the plant, represents an oxygen 

 absorbing area equal to the surface of an ox. Indeed, we might say that the 

 smallest bacteria are almost all surface. 



