382 BOTANICAL GAZETTE [MAY 
the ground and had become true photosynthetic structures. The 
seedlings were examined at 11 different stages exclusive of the 
seed. Chromacetic acid solution was used for fixing, and the 
material was washed, dehydrated, and imbedded in paraffin in 
the usual manner. Various methods of staining were tried. By the 
use of ZIMMERMAN’S method the same difficulties were encountered 
as were experienced by Famrntzin. In the later stages of the 
seedlings the chloroplasts are plainly differentiated, but during 
the early stages they could not be distinguished at all from the 
protein granules in the cell. Sections which had been treated 
with picric acid and then tinged with eosin also showed the. chloro- 
plasts plainly in the later stages of the seedling, but during the 
earlier stages the protein matter, as well as the chloroplasts, takes 
a deep stain and the identity of the latteris uncertain. Sections were 
then treated according to FAMINTZIN’s modification of ZIMMERMAN’S 
method. One series of sections was placed in 30 per cent acetic 
acid for 30 minutes, then washed with running water and trans- 
ferred to 0.2 per cent acid fuchsin. After being allowed to stand 
for 24 hours in this solution, the sections were washed in running 
water for 12 hours, dehydrated in 95 per cent and absolute alcohol, 
cleared in xylol, and mounted in balsam. Another series of sec- 
tions was treated in the same manner, except that they were left 
in the 30 per cent acetic acid 45 minutes. The results obtained 
from the last series were the most satisfactory, and the examination 
of the material was made upon these sections. 
The sections first examined were those of seedlings which were 
fully developed, and the number and position of the chloroplasts 
in the cell were clearly evident (fig. 12). Those next examined 
were of seedlings 12 hours younger, and fig. 11 shows the usual 
position of the chloroplasts at this stage. This method was con- 
tinued step by step back to the original seed, since obviously the 
best means to find the nature of the origin of the chloroplasts is to 
trace them backward in this manner from stages in which there 
can be no doubt at all as to their position and identity. The 
chloroplasts, as shown clearly in figs. 1-12, occupy the normal 
position in the cytoplasm of the cell at all stages of the develop- 
ment of the seedling. In the resting seed, according to our opinion, 
