the Protein Bodies of Zea, Ricinus , and Conopholis. 355 
A little deeper in the endosperm the contents of the cells become very 
much denser, and the vacuoles, as shown in Fig. 6, are replaced by more 
numerous and smaller vacuole-like cavities in which are numerous small 
bodies varying in size, which stain deeply with the iron-haematoxylin and 
appear as dense, black, rounded granules or short rods. They are not 
aggregated in the centre of the cavity at first, as claimed by Wakker, but 
they are distributed about the periphery and throughout the centre. These 
bodies seem to be the same as the rods and granules of Fig. 6, save that 
they are larger, and the impression is that they have collected from the 
groundwork of the cytoplasm into the vacuole- like cavities. Many of the 
cavities have a membrane or boundary that appears as a sharp line, heavier 
than -the nuclear membrane, especially at a later stage of development 
(Fig. 7). In Fig. 8, a slightly older stage, the vacuole-like cavities are 
a little larger, and the contained granules are also larger. The cavities 
vary in size, and in younger cells the granules are smaller and, in all cases, 
numerous (Figs. 7 b, 7 c). Many of the endosperm cells are larger than 
those of Figs. 7 and 8, and in a section more vacuole-like cavities may be 
seen, the number frequently being twelve or more. 
At this stage of development there are also present in the cytoplasm 
many rounded bodies that resemble leucoplasts, together with very small 
and densely staining granules mentioned in a foregoing paragraph (Figs. 7, 8). 
These bodies differ in staining capacity from leucoplasts of the same size ; 
they are larger and more numerous than the starch grains revealed by the 
iodine test made at the same stage of development of the endosperm, and 
they stain a light brown, or pale yellowish colour, with the technique here 
employed. Their colour is almost that of the unstained section, probably 
the colour imparted by the osmic acid used in the killing fluid. They 
contrast strongly with the black granules in the vacuole-like cavities. It is 
probable that these bodies are concerned with the synthesis of oil, and we 
shall return to them in a later paragraph. 
In a careful study of the vacuole-like cavities, containing the densely 
staining granules, in endosperm cells representing different stages of 
maturity, the behaviour of these bodies can be readily followed. In 
Figs. 9 a, 9 b, are shown two such cavities of different sizes, but containing 
many granules that are small and uniform in their dimensions. In Fig. 9 c 
some of the granules seem to be united into a large globular mass. This 
phenomenon is perhaps less frequent than that of Figs. 9 d, ye. Here the 
granules are much larger, especially in Fig. 9 d. In Fig. 9 e it is clear 
that these granules are uniting into a larger mass. This explanation is 
strengthened by what is found in a more mature cell. In an older seed 
(Fig. 10) the cytoplasm is more uniformly granular, there being fewer 
leucoplast-like bodies present that stand out clearly and definitely. 
Instead of vacuole-like cavities, with numerous densely staining granules, 
