294 THE EFFECT OF FOOD 



of the Amazonian region feed the common green par- 

 rot (Chrysotis f estiva) with the fat of large Siluroid 

 fishes, and the birds thus treated become beautifully 

 variegated with red and yellow feathers. In the Ma- 

 layan archipelago, the natives of Gilolo alter in an 

 analogous manner the colours of another parrot, 

 namely, the Lorius garrulus, and thus produce the Lori 

 rajah or King Lory." 



As regards mammals, it is asserted by Nathusius * 

 that if rich and abundant food be supplied to young 

 pigs, it has the direct effect of producing a broader and 

 shorter head. Poor food, on the contrary, produces a 

 longer and narrower head, or a tendency towards the 

 characters of the wild boar. Again, Krockerf has 

 shown that the amount of wool yielded by sheep is 

 greatly influenced by the quantity of food. The fol- 

 lowing are the weights of wool yielded per day by sheep 

 weighing in aggregate 1000 kilograms : 



DIET. KILOGRAMS OP WOOL. 



Scanty winter food, 69 



Plenty of hay, 87 



Good pasture, ....... .96 



Fattening process, 1.081.24 



The quality of the food may considerably affect the 

 organs of digestion. Thus Cuvier $ found that in the 

 wild boar the length of the intestines is to that of the 

 body as 9 to 1, but in the common domestic boar it is as 

 13.5 to 1. It is, of course, impossible to say for certain 

 whether this increased length was the direct result of a 

 more vegetable diet, but it seems highly probable that 



* " Schweineschadel," p. 99; also " Animals and Plants," i. p. 75. 

 f De Varigny's "Experimental Evolution," p. 90. 

 \ " Animals and Plants," i. p. 77. 



