1172 
Journal of Agricultural Research 
Vol. XXX, No. 12 
but the year 1923 was remarkable for 
the fact that 42 varieties out of 49 
showed minimum total astringency for 
the three-year period in that year. 
This was due to the fact that both 
true tannins and astringent nontannins 
were low, 20 varieties having minimum 
tannin while 44 had minimum non¬ 
tannin in 1923. From the results one 
might conclude that in this year high 
sugar content was associated with low 
acidity and low total astringency, and 
that the latter was due to a low con¬ 
tent both of true tannin and astringent 
nontannins. 
The year 1920 had a total of 145 days 
sunlight as the effective period for photo¬ 
synthetic activity. In sugar content 
the crop ran low, only 4 varieties show¬ 
ing the maximum, while 13 had mini¬ 
mum and 14 next-to-minimum figures. 
In acid content there were 13 with 
maximum and 8 with next-to-maximum 
content. The general tendency is to run 
medium to low in sugar and high to 
m'edium in acid, minimum acid and 
maximum sugar being equally rare. 
No astringency determinations were 
made on the fresh juice. 
The year 1922 was the least favorable 
for photosynthetic activity of the four 
comparable years, having only 139 days 
of sunshine in the crop period. The 
sugar content in the crop as a whole 
was lower than in 1923, 17 varieties 
having minimum and 10 next-to-mini¬ 
mum content, while only two had 
maxima. Associated with low sugar 
was an outstanding high acidity, 19 
varieties having maximum and 17 next- 
to-maximum acid content. With high 
acid readings there was associated dis¬ 
tinctly high astringency, 35 having 
the maximum for the three-year 
period. Thirty-three had maximum 
true tannins, while 27 had maximum 
astringent nontannins. Here low sugar 
content, high acidity, and high total 
astringency resulting from high tannin 
and high astringent nontannins are 
found associated. This fact, coupled 
with the fact that the fruit ripened 
somewhat earlier than usual, led to 
delay in picking some varieties until 
they were slightly overripe. The flavor 
of the fruit was so a.Iected by the al¬ 
tered composition that it was difficult 
to convince one’s self that it was fully 
ripe even when it showed all the phys¬ 
ical signs of ripeness. 
This review of the data for the four 
years of normal crop conditions indi¬ 
cates that there is a considerable de¬ 
gree of correlation between the fluctu¬ 
ations in certain chemical constitu¬ 
ents of the grape. High sugar content 
is associated with low or less-than- 
medium acidity and total astringency; 
low sugar content is associated with 
high acidity and high total astrin¬ 
gency. While there are individual ex¬ 
ceptions, there is a clearly marked 
mass tendency, the majority of vari¬ 
eties behaving as one throughout the 
period. It is clear that this mass be¬ 
havior is a response to the seasonal 
conditions of the years concerned. 
The year 1921 has thus far been ex¬ 
cluded from consideration by reason 
of the abnormal conditions of that 
year, namely, a spring freeze with re¬ 
sulting shortening of the growing period 
and reduction of the crop, which pre¬ 
cludes consideration of the data on the 
same basis as those of other years. 
In view of the correlation between 
sugar, acid, and astringency found to 
exist in the other years, it becomes a 
matter of considerable interest to 
know whether this correlation con¬ 
tinues to hold or breaks down in an 
“off-year” of abnormal conditions 
and reduced crop. The data for 1921 
will therefore be reviewed somewhat 
in detail for the.light it may throw 
upon this point. 
The graphic summary on sugar and 
acid content, Figure 1, can not be 
employed for this purpose, for the 
reason that it summarizes results 
which must be segregated in order to 
be properly interpreted. 
As stated in the discussion of seasonal 
conditions for 1921 (p. 1164), 13 va¬ 
rieties suffered no injury from the 
frost. Ten of these, namely, Agawam, 
Cynthiana, Franklin, Herbemont, Le¬ 
noir, Missouri Riesling, Noah, Norton, 
Vergennes, and Wilder, bore crops of 
full normal size. The analytical data 
for these is entirely comparable with 
that for the other years, and may be 
considered on the basis of the sunlight 
received, which exceeded by one day 
that of 1920. Reviewing the data for 
these 10 varieties separately, 1 has 
maximum and 1 next-to-maximum 
sugar, 4 stand in third place, 3 in fourth 
place, and 1 has the minimum. In 
acid 1 has maximum, 1 next-to-maxi¬ 
mum, 3 in third and 3 in fourth place, 
while 2 are minimum. The majority 
of the varieties are consequently mid¬ 
way between extremes, thus recalling 
the situation found in 1920. In as¬ 
tringent constituents, 4 have maxi¬ 
mum total astringency, 1 has the 
minimum, and 5 are intermediate. In 
true tannins 2 have the maximum, 8 
the minimum, while 6 have maximum 
nontannins, and 4 next-to-maximum. 
The general situation with these 10 
varieties is therefore one of medium 
sugar and medium acid content with 
