CHAPTER VII 



DIFFUSION OF SUBSTANCE INTO CELLS TO EXCESS- 

 DIFFUSION- VACUOLES OR "RED SPOTS" THE PROOF 

 THAT THE BLOOD-PLATELET IS A LIVING CELL 



IN this chapter I shall discuss the effects of the diffusion 

 of substances into a cell, when that diffusion occurs to 

 excess. A cell's protoplasm can utilize only a certain 

 amount of the dissolved substance or substances which 

 diffuse into it from the immediate neighbourhood of 

 the cell. One can, however, push this diffusion by the 

 agency of one or both of the factors heat and alkali 

 which increase diffusion, and if w r e do this some of 

 the neighbouring liquid itself passes into the cell and 

 remains suspended as minute droplets in the cytoplasm. 

 These droplets have been called " diffusion- vacuoles." 

 When they were first seen, five years ago, the cells were 

 resting on stained jelly/and since the "diffusion- vacuoles" 

 were stained they were therefore called "red spots." 



Diffusion-vacuoles must not be confounded with 

 the ordinary vacuoles (fig. 16) which appear as colour- 

 less, non-granular patches in leucocytes. Many theories 

 have been advanced regarding these latter vacuoles, 

 but although we have so often seen them, we have no 

 explanation to offer as to their nature. They are 



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