Chapter XV —183— Origin of Vacuoles 



cyanin pigment. The small peripheral vacuoles lack tannin and 

 contain a very concentrated solution of bluish violet anthocyanin 

 pigment which is capable of partially or totally crystalizing into 

 long needle-shaped, dark blue crystals. Another no less interesting 

 example is seen in the exocarp and mesocarp of the fruit of Rubus 

 fructicosus, in which all cells likewise possess two sorts of vacu- 

 oles, the one large, solitary and centrally placed containing, at the 

 same time, tannin and a cherry-red pigment; the other, small, 

 spherical, extremely numerous, and scattered in the parietal layer 

 of the cytoplasm. These latter are without tannin and form at 

 first a brick-red pigment, but when the fruit is mature, there 

 appear in each of these vacuoles, large colloidal bodies, dark 

 violet in color, which show concentric zones. These are the result 

 of the precipitation of the colloidal content of the vacuoles which 

 has absorbed the pigment contained in the vacuoles. At maturity 

 the vacuolar sap changes from brick-red to pale violet, then to 

 white, whereas blackish, violet-blue crystals shaped like needles, 

 or sphaerocrystals, are deposited in the interior of the vacuole 

 between the colloidal bodies. In certain parts of the epidermis of 

 the petals of Hibiscus syriacus also, there are found in each cell 

 a large central vacuole, enclosing tannin as well as a raspberry-red 

 anthocyanin pigment, and small peripheral vacuoles enclosing a 

 mauve pigment. 



In all the cases which we have just examined, the two categories 

 of vacuoles contain colloidal substances and have the property of 

 accumulating vital dyes, but this is not, however, universal. In a 

 very great number of cases (in the epidermis of leaves, stem and 

 petals of roses, in the petals of Lathyrus odoratus, Prunus japon- 

 ica, Camellia japonica, Tropaeolum majus, in leaves of Canna in- 

 dica, etc.), there are found together constantly, in each cell, two 

 categories of vacuoles: a large central vacuole containing tannins 

 or other colloidal substances as well as an anthocyanin pigment, 

 and small colorless vacuoles seemingly without any colloidal sub- 

 stances. Those of the second category sometimes contain very 

 minute crystals showing Brownian movement. In the elongated 

 cells of the inner portion of the fleshy pericarp of the fig there are 

 two categories of vacuoles of very curious appearance, each vary- 

 ing both in number and dimension in the cell. One type contains 

 violet-red anthocyanin pigment together with colloidal substances 

 and is very variable in shape, the larger among these having irreg- 

 ular contours which give them an angular appearance, the smaller 

 ones being chondriosome-shaped elements. The other type is color- 

 less, lacking in colloidal substance and all of them, no matter what 

 their dimensions, appear perfectly spherical. In this case, the vacu- 

 oles which do not contain tannins or other colloidal substances never 

 stain, which seems therefore to add further proof that vital stain- 

 ing of the vacuole is due exclusively to the presence in them of 

 colloidal substances. The case of the pericarp of the fig is par- 

 ticularly interesting because it shows us that the shape of the 

 vacuoles, whether irregular or like that of the chondriosomes, seems 



