CIRCUMSTANCES AFFECTING DIGESTIBILITY 149 



EXPERIMENTS WITH PIGS. 



* The numbers in these cases are the mean of a few experiments. 



(4) Experiments with Geese and Fowls. — Birds have 

 apparently no power of digesting vegetable fibre ; the 

 food passes too quickly through the system for the 

 fibre to be attacked. 



Circumstances affecting Digestibility. — The indi- 

 vidual character of the animal undoubtedly affects the 

 proportion digested. Of two animals supplied with 

 the same food, one will often persistently digest a 

 larger proportion than the other. In young animals 

 the digestive power is apparently equal to that of 

 animals of full age. Sheep from six to fourteen months 

 old showed no distinct change in digestive capacity. 



Differences in the quantity of the daily ration of hay 

 do not sensibly affect the proportion digested ; an 

 animal will not digest more by being starved. With, 



