COMPAEATIVE NUTRITIVE VALUE OF FOODS 161 



To obtain the production value in terms of starch, 

 the calculation is still simpler : — 



Fat X 2'3 + Albuminoids + Carbohydrates. 



The totals obtained by these calculations express the 

 value of each food, both for maintenance and production 

 purposes, in terms of dry, digestible starch.^ The table 

 also shows what weight of each food is equivalent in 

 effect to 1 lb. of starch. 



The different rank which a fibrous food takes accord- 

 ing to the work which it has to perform is clearly 

 shown in this table. It appears that 2 lbs. of oat 

 straw, or wheat straw, may replace 1 lb. of corn if 

 the ox or sheep is merely on a maintenance diet ; but 

 that 1 lb. of corn will have as great an effect as 

 4 lbs. of oat straw, or 8 lbs. of wheat straw, when the 

 animal has to grow or fatten. 



The equivalent quantities of different foods shown 

 in the table agree fairly with those ascertained by 

 actual feeding experiments. Thus the very numerous, 

 but somewhat rough, Danish experiments with fatten- 

 ing pigs, showed that 4 lbs. of potatoes, or 7 — 8 lbs. 

 of mangel, vs'ould adequately replace 1 lb. of corn meal 

 (rye, barley, or maize). In American experiments with 

 pigs, 4J lbs. of potatoes were equivalent to 1 lb. of 

 maize meal. In the old French estimates, 5 lbs. of 

 turnips, or ^ lb. of peas or barley, were reckoned equal 

 to 1 lb. of best meadow hay. 



The table teaches us that an equal weight of corn 



' It sbould, of course, be remembered that starch has a different 

 value for maintenance and production, the standard unit does not 

 therefore represent the same number of Calories on both sides of the 

 table on p. 160. 



11 



