Jan. io, 1914 
Environmental Influences on Wheat 
285 
tively small r 61 e played by the soil in influencing the protein content of 
wheat. There was a greater similarity between the protein contents of 
the samples grown in Maryland and California, both relatively humid 
regions, than between the protein contents of samples from either of 
these localities and those from Kansas, which has a comparatively dry 
climate. 
There are a few exceptions, however, to the rule that soil influences the 
composition of wheat to only a slight degree. Among the most striking 
of these were the protein results obtained in 1909 in California on Cali¬ 
fornia soil, in 1910 and 1912 in California on Maryland soil, as well as in 
Kansas on Kansas check soil; that is, 4 out of 42 cases did not follow 
the general rule. Since about 90 per cent of the results obtained followed 
the general rule, and the exceptions noted were in different localities 
and on different soils and not always on the same soil in any locality, it 
is probably safe to assume that the contrary results given by the other 10 
per cent of samples were accidental. These few exceptions among the 
prevailing regularities may serve to emphasize the fact, too frequently 
overlooked in plat experiments of this kind where many factors may affect 
the results, that a regularity needs to be traced through a great number 
of individual instances before it is safe to draw conclusions from it. 
Thus, in this experiment a consideration of the data from the 1909 crop 
alone might show that the soil has a marked determining influence upon 
the protein content and that the California soil tends to produce a wheat 
of relatively high protein content. That such a conclusion would be 
erroneous is evidenced by practically all the data of the three following 
years, for in no other case during 1910, 1911, and 1912 was there a larger 
amount of protein in wheat grown on the California soil than in that 
grown on the two other soils. In fact, those wheats were invariably 
lower in protein content. 
While these exceptions may be considered as purely accidental, the 
following question is suggested by such variations from the rule: Is there 
in the physical, chemical, or biological characteristics of the soil a real 
difference which at first exerts a determining influence on the composi¬ 
tion of the crop, but which may be obliterated in the course of a year or 
two after putting the soil down in a different locality? Some weight is 
lent to such a hypothesis by the fact that the slight differences in protein 
content in the crops grown in Maryland the first year after the exchange 
of soils were much the same as the exceptionally great differences in the 
crops grown in California. Unfortunately, the Kansas crop was a com¬ 
plete failure, and it is impossible, therefore, to know in what way the 
soil there would have influenced the composition of the crop during the 
first year. To answer this question, more observations during the first 
few years of similar soil exchange experiments would be necessary, using 
larger plats to partly eliminate any tendency for soils to equalize after 
being together in one locality, if such a tendency does exist. 
