the Protein Bodies of Zea, Ricinns, and Conopholis. 359 
in the pollen mother-cells of Lilium candidum , for example, there are 
mitochondria which do not become leucoplasts. He seems to prefer that 
all small granules and rods in the cytoplasm be called mitochondria and 
chondrioconts, whether they do or do not develop into known plastids. 
Emberger (1920) recognizes in the cells of the developing sporangium 
of the fern plastids and mitochondria, stating that, in the cells of the 
maturing sporangium, chloroplasts revert to mitochondria. 
In the description of the origin of the plastids here under consideration 
in this paper, I have not used the term mitochondria or chondriosome 
to designate any body in the cell. In meristematic cells of most plants, 
certainly in all examined by the writer, including fungi, many very small and 
densely staining granules and rods are to be readily observed. This statement 
seems to apply equally well to cells of certain animals. It is to be regretted 
that too many observers have been content to demonstrate in cells of both 
plants and animals the mere presence of these small bodies, referring 
to them merely as mitochondria or chondrosomes, without any effort to 
determine what such bodies might develop into. In the present state of our 
knowledge, there is certainly nothing to be gained by the mere demonstra- 
tion of small objects under the names mitochondria, chondrioconts, &c. In- 
asmuch as these terms have been applied to different objects in both animals 
and plants, it is questionable whether they should continue in use. 
In addition to leucoplasts and chloroplasts having their origin in 
definite primordia, which are permanent organs of the cell, the writer 
feels justified in adding protein plastids and perhaps also oil plastids. 
In the endosperm of Zea Mays there seems to be no doubt that the 
protein granules, known as aleurone grains in the outer layer, are derived 
from definite and pre-existing primordia that first appear as small granules 
or short rods. As these bodies elaborate the protein they increase in size, 
many assuming large proportions. They stain definitely and densely with 
protoplasmic stains. In Zea the writer is not prepared to state whether 
two or more of these protein granules fuse into larger masses as the seed 
matures. 
In Ricinns the protein granules take their origin likewise in definite 
primordia. These generally aggregate in vacuole-like cavities, and, as the 
cells mature, the product of their elaboration unites into larger masses, 
known as the aleurone grains. Within these large masses a part of the pro- 
tein takes on the form of a crystal or crystals near which appears the body 
known as the globoid. The amorphous protein surrounding the crystalloid 
does not take the stain in the preparations. This aggregation of the pro- 
tein plastids in cavities may be correlated with the presence of oil which is 
elaborated simultaneously in the same cells. 
The writer has in a foregoing paragraph called attention to leuco- 
plast-like bodies, which, however, did not react to the stains like normal 
