CHAPTER III 



THE HISTOLOGICAL DISTRIBUTION OF ANTHOCYANINS 



When tissues containing anthocyanin are examined microscopically, 

 in the majority of cases the pigment is found to be in solution in the 

 cell-sap, which, of course, occupies the vacuole or vacuoles of the cell. 

 We know, as Gertz (19) points out, from the researches of de Vries (141) 

 and Pfeffer 1 that in living cells the protoplasm is impermeable to antho- 

 cyanin in the cell-sap. But when the protoplasm is dead and semi- 

 permeability ceases, anthocyanin exosmoses out of the cell, and at the 

 same time it is often taken up, like a stain, by the protoplasm and 

 nucleus 2 . 



From the condition of solution in the cell-sap, two deviations are 

 possible : first, in tissues which gradually die or become woody, the 

 anthocyanin may be absorbed into the substance of the cell- wall, thereby 

 causing the latter structure to become coloured ; secondly, the concen- 

 tration of anthocyanin in living cells may become so great that the 



1 Pfeffer, W., Osmolische Untersuchungen, Leipzig, 1877 (pp. 134, 135). 



2 Staining of the nucleus under these conditions has been noted by Hartig, de Vries 

 and Molisch. 



Hartig, Th., 'Chlorogen,' Bot. Ztg., Berlin, 1854, xn, pp. 553-55(5 (p. 555). 



Hartig, Th., 'Ueber das Verfahren bei Behandlung des Zellenkerns mit Farbstoffen,' 

 Bot. Ztg., Berlin, 1854, xn, pp. 877-881 (p. 879). 



Hartig, Th., 'Ueber die Bewegung des Saftes in den Holzpflanzen.' Bot. Ztg., Leipzig, 

 1862, xx, pp. 89-94 (p. 93). 



Vries, H. de, ' Plasraolytische Studien iiber die Wand der Vacuolen,' Jdhrb. wiss. 

 Bot., Berlin, 1885, xvi, pp. 465-593. 



Molisch, H., Untersuchungen iiber das Erfrieren der Pflanzen, Jena, 1897 (pp. 28, 29). 



On account of this property, anthocyanin has been used as a stain for liistological 

 purposes. The red anthocyanin of Cabbage has been employed in this way by Tait, 

 Gierke, Flesch (159), and Claudius (184); Lavdowsky (160) also recommends anthocyanin 

 from Myrtillus berries. 



Tait, L., 'On the Freezing Process for Section-Cutting,' J. Anat. Physiol., London, 

 1875, ser. 2, vin, pp. 249-258. 



Gierke, H., 'Farberei zu mikroskopischen Zwecken,' Zs. wiss. Mikrosk., Braunschweig, 

 1884, i, pp. 62-100, 372-408, 497-557 (p. 99). 



