SYMBIOLOGY— THE BIOLOGICAL RELATIONSHIPS OF ORGANISMS 135 



e. Chloro-sph(Brocytes.—Thesei are comparatively few in the ripe to- 

 mato. In the unripe tomato they are very abundant. They may also 

 contain brown chromophores and they generally have distinct nuclei. 

 The chlorophyll granules are elliptical in form and are identical with the 

 chlorophyll granules of the peripheral pulp cells of the tomato. 



Chlorophyll granules are very short lived outside of the mother cell. 

 In the hanging drop they disintegrate very readily, much more readily 

 than do the brown coloring bodies. 



f. Amylo-spharocytes. — These are always nucleated and are simply 

 nearly mature sphaerocytes which contain a few starch granules. They 

 may also contain brown chromophores and chlorophyll granules. 



Pig. 48. — Spheerocytes o£ the grape. A, C, Mature pulp cells. B, D, sphaerocytes 

 in various stages of devolpment. 



Observations in the hanging drop showed that the chloro-sphaerocyte 

 and the amylo-sphaerocyte died as quickly as did the mature pulp cells. 

 The amyloplastids are however quite resistent and under certain condi- 

 tions will continue growth for some time in the hanging drop. Asparagin 

 (i-iooo) appears to stimulate the amyloplastids. 



Hanging drops of the tomato pulp rich in sphaerocytes, incubated at 

 30° to 35° C. showed that many of the nucleo-sphaerocytes kept alive for 

 fifteen months and longer, whereas most other forms, including the 

 mature tissue cells, usually died within a period of twenty-four hours. 

 The most marked change in the living nucleo-sphaerocytes in the hanging 

 drop was a slight increase in size of the cell and of the nucleus and a very 

 pronounced darkening of the plasmic substance. At first the vacuoles 

 increased in number and also in size, some of the more peripheral ones 



