388 
IOWA ACADEMY OP SCIENCE 
*= * =» to say that the baby does these things without know- 
ing how to do them, and without ever having done them before, 
and continues to do them by a series of lifelong flukes ? ’ ’ And 
again : ‘ ‘ It is * ^ those who do not know that they know 
so much who have the firmest grip of their knowledge ’ Or this : 
“Perfect ignorance and perfect knowledge are alike unself con- 
scious”. 
The Butler argument is forceful, because it seems so logical 
and true. 
“APPETITE” STUDIES WITH SODIUM CHLORIDE. 
It has been demonstrated in a recent investigation, 1914, by 
Evvard^^ that well-grown young swine of approximately 150 
pounds average weight make better use of common salt (sodium 
chloride) when it is fed ad libitum, it being accessible all of the 
time, than where it is mixed with the daily ration in varying pro- 
portions. The young swine in question received a basal ration 
of corn and oil meal (the flax grain from which a large portion 
of the oil had been extracted with heat and pressure) . This basal 
mixture was constant, as regards quality, throughout the period ; 
it being composed of 6.1 parts corn to 1 part linseed oil meal. 
There were 40 individuals in the experiment. These were di- 
vided, or rather distributed into five lots of eight each. These 
were fed as follows : 
Lot I Basal Ration (as given). 
Lot II Basal Ration plus 18^- grams of salt daily, mixed. 
Lot III Basal Ration plus 36=*^ grams of salt daily, mixed. 
Lot IV Basal Ration plus 72^^ grams of salt daily, mixed. 
* Lot V Basal Ration plus salt ad libitum. (The average 
consumption throughout the period on the average 
was 27.56®“ grams, which is midway between Lots II 
and III; the amount eaten varied, however, being as 
high as 42.6 grams early in the. period and gradually 
reducing to less than 8 grams daily at the close.) 
In brief, it may be said that there was a check period of 90 
days preliminary run in order to determine just how the indi- 
vidual lots would gain. During this period the feed quantity 
and quality was kept constant in each lot, and no salt was al- 
lowed. Following this preliminary there came 71 days, however, 
in which salt was given to each lot of 8 hogs as stated. 
siEvvard, John M. : unpublished data. To be published in full in Bulletin 
form later. Results Animal Husbandry Section, Iowa Experiment Station, 
320n basis “Daily Consumption per Pig” we have respectively: Lot I, — 
none; Lot II, — 2,25; III, — 4,50; IV, — 9,00; and Lot V, — 3,45 grams. 
