Guilliermond - Atkinson 



150 



Cytoplasm 



other dyes which do not have a predilection for the vacuoles. More- 

 over, the chondriosome-shaped vacuoles are of temporary nature 

 and, even beginning with the first stages of cellular development, 

 these vacuoles take in water and become transformed into large 

 vacuoles, whereas it is known that the chondriosomes persist dur- 

 ing the entire life of the cell. The only question that could be 

 asked was whether, as we had supposed, the vacuoles were not 

 derived in some cases from the chondriosomes. It was not logical 

 to say that the chondriome and the vacuome were one and the 

 same thing. The interpretation of Dangeard has therefore been 

 abandoned for a long time now, even apparently by its author, 

 although without explicit statement to that effect. 



Fig. 94. — Barley root. Stages in development of the 

 vacuolar system. 1-5, meristem; 6-8, adjacent region of differ- 

 entiation; 9, mature cells of cortical parenchyma. Vital staining 

 with neutral red. 



Our investigations, beginning with that period, gave more 

 details and indeed confirmed the observations of P. A. Dangeard 

 in so far as the development of the vacuoles is concerned, but 

 they showed that the chondriosome-shaped vacuoles and the chon- 

 driosomes have in common only their shape, and that the vacuome 

 is a system completely independent of the chondriome. They 

 showed, furthermore, that the vacuoles are not characterized by a 

 specific substance corresponding to metachromatin and that the 

 colloids which the vacuoles contain are substances of very diverse 

 nature, having as a common property only their ability to absorb 

 vital stains. These facts were afterwards verified by a large num- 

 ber of cytologists and are today definitely accepted. The vacuoles 

 do not, in general, stain by mitochondrial techniques and it is the 

 very complex case of the leaflets of the rose which has caused all 

 the difficulty. It has been seen that in the cells in the young teeth of 



