62 FARM ANIMALS 
15. Other standards in recent years.—Since the intro- 
duction of the Wolff standards other investigators have 
sought simpler means of measuring the nutrient content 
of feeding stuffs. The idea of using energy values ex- 
pressed’ in terms of starch equivalent in the computation 
of rations for farm animals originated with Dr. Kellner of 
Germany. Following him came Dr. Henry Prentiss 
Armsby of Pennsylvania, who 
measures the energy content by 
the therms of net energy they. 
contain. The two methods are 
identical, but neither method 
has been before the public long 
enough to be well ‘known or to 
be put to practical use. The 
value of any material as a fuel 
substance will naturally depend 
on how much chemical energy 
that material contains. Both the 
quantity and the quality must 
be determined in order to get a 
fair measure of its energy value. 
Quite generally the fuel value of 
feeding stuffs is expressed in 
Roni calories. A calorie is the amount 
Enon Micicne: Coak of heat required to raise one 
As the animal, grows the ration pound of water four degrees 
Fahrenheit. A therm is the 
quantity of heat required to raise the temperature of 
1000 kilograms of water one degree centigrade. 
