1922] RANDOLPH—MAIZE 365 
Intra-vitam stains, a number of which have been employed, 
have unexpectedly failed to give a definite reaction to the pro- 
plastids. Such stains as Janus green B, violet of Dahlia, neutral 
red, etc., have given uncertain results. In some cases the pro- 
plastids have appeared to be faintly stained by Janus green B, 
but in no case has a strong staining reaction been observed, neither 
has it been found possible to differentiate different kinds of minute 
bodies in the cytoplasm of the cell. Cowpry (11) reported that 
plant mitochondria are stained with Janus green B, but that it is 
much more difficult to obtain a good stain in plant cells than in 
animal cells because of their well developed cellulose walls. A 
similar conclusion has been reached by other plant workers. 
Chondriosomes in both plant and animal cells were first observed 
in fixed and stained preparations, and the lack of uniformity in 
the results of early workers may have been largely due to the use 
of different fixatives and alterations resulting from poor fixation, 
as has been pointed out above. The special methods of fixation 
and staining commonly used in a study of the cytoplasm have been 
fully described in recent literature (CowpRY 11, GUILLIERMOND 31, 
KINGSBURY 39): In general chondriosomes have been found to 
be preserved by potassium bichromate, chromic acid, neutral 
formalin, and osmic acid, and these are the chief ingredients of 
the fixatives used for their study. Such substances as alcohol, 
ether, chloroform, and acetic acid dissolve the chondriosomes or 
produce profound changes in their shape, etc. 
The methods. of fixation ordinarily employed often appear to 
Preserve quite faithfully ‘the structures in question, but direct 
observation on the living’cell is unquestionably of far greater value, 
since it obviates the possibility of misinterpretation to a very large 
extent. Furthermore, in tissues which are favorable for a study 
of the living cells the cytoplasmic inclusions are sharply delimited, 
and actually are more ‘easily observed than in fixed and stained 
cells. Conflicting results have been obtained by those who have 
attempted, to demonstrate the existence of different kinds of 
cytoplasmic bodies by the use of various fixing and staining 
methods. The use of such methods in this study has failed to 
furnish convincing evidence for the presence of more than one 
. type of proplastid in the initial stages. 
