1911] MILLER—ORIGIN OF CHLOROPLASTS 379 
Mikoscu (2), after an examination of the seeds and seedlings 
of Helianthus annuus, reached the conclusion that there are no 
chromatophores present in the resting seeds of this plant, but that 
during germination the chloroplasts arise directly from the proto- 
_ plasm of the cells. He holds that their origin is due to the 
condensation of the cell plasma in definite places. This condensa- 
tion he thinks is probably brought about by a loss of water in those 
parts. The condensed parts soon take on the green color and 
become the chloroplasts. This process of formation goes on inde- 
pendently of light. The bodies thus formed are at first rod or 
spindle-shaped, but later assume the typical disk shape of the 
choloroplasts. 
BELzunG (3), after a lengthy investigation of the ripening seeds 
as well as of the mature seeds and seedlings of many plants, came to 
the following conclusions: (1) that the free growth of starch grains 
can take place without the intervention of leucoplasts; (2) that 
the chloroplasts are formed directly by a differentiation of the 
Protoplasm; (3) that the chloroplasts can also be formed at the 
expense of the starch grains which have their origin in the cyto- 
plasm of the cell. The severe criticism of his work by SCHIMPER 
(4) led Betzune to traverse anew his previous work, and in a 
Paper published in 1891 (5) he verified his previous conclusions. 
In this investigation he used as material Phaseolus vulgaris, 
Lupinus albus, Lupinus elegans, Faba vulgaris, Pisum sativum, 
and other plants. According to his observations, the young 
embryo contains no chloroplasts. The starch grains formed in 
the young embryo are laid down in the vacuoles of the protoplasm. 
He holds that those who claim that starch grains are the product of 
leucoplasts are in error, and that the leucoplasts defined by differ- 
ent investigators are simply the boundaries of the vacuoles in the 
Protoplasm. The green color of the embryo in many plants is 
| due to a green pigment distributed throughout the protoplasm of 
the cell, According to BeLzunG, therefore, there are no chroma- 
tophores present in the embryo, and consequently none in the 
Mature seeds. At germination the simple starch grains of the 
seed disintegrate, and numerous compound grains of transitory 
Starch appear in various parts of the protoplasm. These com- 
