102 BOTANICAL GAZETTE [FEBRUARY 
from spring to autumn. It is evident that the protein content of 
green and mottled Coleus leaves does not parallel that of the green 
and etiolated leaves of PAttapin. If it resembles the protein 
change with progress of the growing season, it is at least much more 
rapid. It is probably quite similar to the rapid changes just 
preceding leaf fall in autumn. 
The work of ScHULZzE and Scutitz (44) may again be relied upon 
to show the normal changes which take place in Acer Negundo. 
TABLE X 
NITROGEN PRESENT IN Acer Negundo LEAVES AT VARIOUS TIMES OF YEAR 
Protein N May 7 | June6 | July 5 | August 2 September 3| September 25 
Rea SaaS O.934 |-O.0734 13211 10.864 | 6.707 0.628 
Diba taietic des material) 4.304 | 3.906 | 4.068 | 3.745 | 3.163 2120 
The magnitude of the changes in the protein content of Acer 
Negundo is in harmony with that of Coleus, except that the changes 
in the latter are much more precipitous. 
MEYER (38) made macroscopic tests for proteins in the leaves 
of Tropaeolum by means of the xanthoproteic reaction. The 
natural color of the leaves was noted and compared with the depth 
of color which was produced by the xanthoproteic test. He 
found that as the green color of the leaf disappeared, the xantho- 
proteic reaction became less and less, or, in other words, as the 
protein of the chloroplast decreased, the chlorophyll in the chloro- 
plast decreased also. 
TABLE XI 
XANTHOPROTEIC REACTION OF NORMAL ILLUMINATED 
OWING LEAVES OF Trapaeolum 
ries _ WAU ei ia tei bie ayes 5 to 4* 
Pras Cee wee ee eee ee E SEH CEO G TON eu Ta eee 3to4 
Bright GEOR ee a ee, 
VGUOW BOO i a i ss 2 to 3 
NOUOW os cay Cea vies os ps a ea es 2 
Bega VOW ey, ee I to2 
th Pat 3 Pe 4 + 
TL 1 +1 / = +1 + 
ihe larger the number the greater 
In the leaves of the plane tree (Platanus occidentalis) TUCKER 
and ToLtens found that the protein nitrogen decreased gradually 
