36 
Colorado Experiment Station 
We have said nothing about the ripening period. The principal 
reason for this is, that in 1913 the transference of the nitrogen from 
the plant to the seed, or its elimination from the plant, went on 
till the total in the plant was reduced far below what it was during 
the vegetative period; this was not the case in 1915. The total ni¬ 
trogen in the plant remained high and the amount in the head did 
not increase as it did in 1913. In 1913 the season was very favora¬ 
ble, in 1915 it was quite unfavorable for the maturing of a good 
crop. One .result of the unfavorable crop season of 1915 was the de¬ 
velopment of rust on all three varieties of wheat grown, but it injured 
the Red Fife, whose composition we have given for two years, 1913 
and 1915, perhaps the least of the three. The indications are that 
the normal processes in the wheat during the ripening period were 
seriously interfered with, and while the changes may have been nor¬ 
mal in their general character, which admits of a doubt, they were 
at least incomplete. - The severe attack of rust was a direct result of 
the weather conditions. It was fortunate for us that we had chosen 
the Red Fife for our study. Had we chosen Defiance we would have 
been unable to obtain any results that we would have felt willing to 
use, because the crop was ruined, especially on those plots to which 
sodic nitrate had been applied. That these plots were more suscep¬ 
tible than the others to attack by this fungus can scarcely admit of 
a doubt. We might express the reasons otherwise. The plants were 
large, succulent, badly lodged, almost continuously wet, and rusted. 
The other plots were very severely attacked, but they were not so 
severely, and the wheat yielded was better than that of the nitrate 
plots, though very far from good. The Red Fife is naturally several 
days earlier and probably more resistant to the effects of rust than 
the Defiance. It is from such considerations that we conclude that 
the course of the changes in the plant, including also the heads dur¬ 
ing the ripening period of 1915, was greatly interfered with by 
this fungus, and that this is the cause of the results obtained. The 
weather conditions, especially those features which kept the plants 
continuously wet, were accountable for the low nitrogen in the plants 
up to the end of July. But during the ripening period the imme¬ 
diate cause of abnormal development was the severely diseased con¬ 
dition of the plants, and the effects of the weather conditions proper 
are concealed by the effects of the rust. 
The ammonic, amid and nitric nitrogen in the plants are con¬ 
sidered of less importance in this question than the total and pro- 
teid nitrogen. The presence of nitric nitrogen in the wheat plant is 
probably altogether dependent upon an accidental excessive supply 
in the soil, while the ammonic and amid nitrogen are intermediate 
and transient forms in the plant. The proteid nitrogen, on the other 
