42 BULLETIN 1300, U. S. DEPARTMENT OE AGRICULTURE 
Thus the price of corn, the chief factor in the cost of production of 
hogs, plays as great a part in determining the bids made by the packers 
for the hogs as does the supply. 
The highest degrees of determination by preceding conditions are 
obtained by taking into account both summer weights and corn 
prices. Summer price is determined 76 per cent by the price of corn 
for the preceding year combined with the two preceding summer 
weights. Winter price is determined 71 per cent by the two pre- 
ceding corn prices combined with the second preceding summer 
weight. Roughly speaking, the price paid for hogs by the packers 
is determined somewhat more than one-third by the price of the corn 
on which the hogs were raised and fattened, a little more by the 
supply of hogs, and about one-fourth by unknown factors which 
would include fluctuations in the demand for pork products. 
As already indicated, the correlations of hog price with preceding 
corn prices and summer weights are much too high to be explained 
through the mediation of the number and weight of the hogs actually 
bought by the packers. In the long run, the price of hogs is based 
more on the total supply of hogs in the country and on the profits 
of hog raising as affected by corn prices than on the actual market 
receipts. This probably means that the packer's demand is based 
to a large extent on current and prospective general conditions: 
also that there is a prompt reaction (positive) of hog prices on 
market shipments, which tends to reduce the negative correlations 
between pack and price. 
SUMMER SLAUGHTER 
The size of the preceding corn crop is the most important single 
factor in determining summer slaughter (Table 8, fig. 22). The 
correlation of +0.61 means 37 per cent determination. The high 
correlation with the live weight of the preceding winter (+0.50) is 
in the main due to the common influence of the corn crop. To some 
extent, however, it should be due to heavy breeding in the spring 
a year before, which should have a direct influence on the given 
summer slaughter and, as we have seen, has an important influence on 
winter weight. 
Incidentally, summer pork production shows a much higher corre- 
lation with the preceding winter weight ( + 0.72). This would not 
be consistent with the correlation of +0.50 were they taken over the 
same period of years. The years 1871 to 1915 were used for slaughter 
and 1889 to 1915 for pork production. This discrepancy is not due 
to a greater influence of corn crop in the later years (correlations 
+ 0.60 for slaughter, and +0.64 for pork) . It may be due to increas- 
ing spring breeding. 
The correlation between summer slaughter and the live weight of 
the preceding summer ( + 0.48) is a consequence of the common influ- 
ence of heavy (or light) breeding on the two variables. 
The high correlation with the preceding corn crop ( + 0.61) offers 
some difficulties. Breeding in the preceding fall, based on the size 
of the corn crop, would determine a large spring-pig crop but the 
greater part of these pigs would not be ready for slaughter until after 
October 31. The abundance of corn left over from a big crop, how- 
ever, would permit early fattening and marketing, which would allow 
advantage to be taken of the relatively high summer prices. The 
