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IOWA ACADEMY OP SCIENCE 
2. The somewhat natural tendency of the free-choice curves 
to gradually change without any general tendency towards 
abrupt differences. (This omits consideration of the ten day 
periodic variations.) 
3. A ‘‘period of readjustment” is noticeable in the first 30 
days, as it takes the pigs a few weeks to adjust themselves to 
the new conditions of eating, — new feeds, new quarters, new en- 
vironment, and other not hitherto experienced factors. 
4. The fairly close agreement between the Dietrich or Illinois 
standard and the “appetite” curves. 
5. The contrasted character of the Wolff-Lehmann curves 
and the ‘ ‘ appetite ones. ’ ’ The type of curve is different in these 
two instances. 
Peculiarly enough, the pigs ate somewhat as the Dietrich Illi- 
nois standard would allow, but without the specific rises and 
falls. 
While the breaks in the curves are noticeable, especially on 
the 135th day of age, the 145th and the 155th, yet these are 
probably due indirectly to technique, climatic and other imme- 
diate factors. After the pigs reached the age of 160 days, how- 
ever, it is quite noticeable that the curves are more uniform. 
This is explained somewhat by an improvement in the method 
of “weighing back” the uneaten feed. At this time a constant 
hour was set aside for this procedure at the end of every ten 
day period; whereas formerly the feeds were “weighed back” 
sometime during the forenoon, considered as from 7 A. M. to 
12 M. At any rate, the general natural tendency. of the “free 
choice” “appetite” curves is well brought out; the data from a 
large number of trials would smooth out the appetite curves. 
After the 245th day of age the Dietrich standard has not been 
formulated, hence it is incomplete from that point on. 
The Wolff-Lehmann standard calls for a lesser amount of pro- 
tein than does the ‘ ‘ appetite ’ ^ in most of the growing period, or 
until the pigs reach the age of practically 190 days, at which 
time the requirement is in excess of the appetite. Of course, it 
is entirely probable that if the protein allowance is based on 
the Wolff-Lehmann standard early in the period the pigs will 
tend to compensate for this deficiency later. We note this to a 
considerable extent in practice : pigs that have been starved for 
amino-acid mixtures during the early part of their life, do, when 
later given a free opportunity to eat of an abundance of amipo- 
