224 THE UNIVERSITY SCIENCE BULLETIN. 



In the thin-walled parenchyma of the cortex, droplets of oil are 

 of frequent occurrence, and these were discovered to be held in 

 the stroma of spherical elaioplasts, which in unstained sections 

 appear simply as highly refractive bodies. When treated with 

 chloroform or ether for twenty-four hours and then tested with 

 stains for oil, no oil was demonstrated, but irrigation on a slide 

 with solvents of oil for ten to fifteen minutes did not cause all of 

 the oil to disappear. Sections from celloidin material, which had 

 been fixed with one per cent chromacetic acid, tested with Sudan 

 III, alkanin and chloroiodide of zinc, showed these bodies as 

 globular masses reacting as oil. Strasburger ('13) makes the 

 statement that the chromacetic acid fixitive causes percipitation 

 of the stroma of elaioplasts and renders the oil less soluble. This 

 may explain oil remaining in the stroma of the elaioplasts through 

 the celloidin process in which solvents of oil are employed. Saf- 

 ranin-haematoxylin stain and the three-color stain showed these 

 bodies as purplish, spherical, reticulate structures. The elaioplasts 

 in the cells of the root sometimes lie next to the nucleus, but a 

 constant relation was not found. The cytoplasm in the older 

 cells of the cortex is only a thin layer lining the wall, so that there 

 the elaioplasts are against the wall; usually only one to a cell 

 (figs. 17 and 18). 



Beer ('09) in his work on Gaillardia sustains the theory of 

 Wakker ( '88) that the elaioplasts are formed by the aggregation 

 and fusion of the leuocoplasts in the cell. His work seems to 

 give conclusive evidence for this mode of formation in the plant 

 studied. He foimd elaioplasts in different stages of development, 

 and observed living cells in which the process was going on where 

 cell divisions had long since ceased; but Politis ('11), in his work 

 on the development of the elaioplasts in Ornithogallum umhellatum 

 bulbs, maintains that they are formed by the cytoplasm, almost 

 simultaneously with nuclear division. He states that the stroma 

 of the elaioplasts stains with the nuclear stains, reacting like the 

 nucleolus; and since they also are dissolved with nuclear solvents, 

 he maintains the elaioplasts are of nuclear origin and gives the 

 fact of the close association with the nucleus and the chemical 

 reactions as basis for this conclusion. ^^J^^-^jj 



In Ahutilon I found elaioplasts were present in the actively 

 growing parts, such as floral organs, growing apices of stem, 

 young seedlings, barely sprouted seeds, and also in root sections 

 in all stages of development. When the older parts of the stem 

 were tested no elaioplasts could be demonstrated. The^presence 



