GuilHermond - Atkinson 



— 74 



Cytoplasm 



to distinguish the chondriome. It is only in foliar primordia in 

 which the chlorophyll is beginning to appear that the chondrioconts 

 are visible. They are here impregnated with chlorophyll and all 

 the forms can be followed in sequence from these elements to the 

 large chloroplasts of mature cells. The other chondriosomes, how- 

 ever, are difficult to distinguish. The cells of the mature leaves 

 are, on the other hand, very transparent and very favorable for 



Fig. 37. — Development of the chondriome in the castor 



bean root. 1-6, meristem; 7-11, differentiating cells, plastids 



forming starch; 12, differentiated parenchyma cell of the central 

 cylinder. Regaud's method. 



the study of living cells. In them can be seen all that Regaud's 

 method brings out and it is possible to distinguish with great 

 clearness within the hyalin, homogeneous cytoplasm, large chloro- 

 plasts, often in the process of dividing, interspersed with chondrio- 

 conts whose slightly higher refractivity distinguishes them from 

 the cytoplasm. 



It is easily possible to follow the formation of chloroplasts by 

 a study of the development of the chondriome in other buds, among 

 them barley which was the object of our first research (1911). 

 Here also, the chloroplasts are derived from chondrioconts which 

 thicken, and on their long axes form small swellings which after- 



