B. IX.] THE HISTORY OF ANIMALS. 277 



comes again when it sets, for sometimes it retreats before 

 the cold, and sometimes before the heat. The hoopoe also 

 changes its colour and its forms, as ^iEschylus writes. " He 

 had variegated this hoopoe, the witness of its own evils, and 

 has displayed the bold bird that dwells in the rock in 

 all armour. In the early spring it shakes the feathers 

 of the white hawk; for it has two forms, that of the 

 young bird and of itself, from one origin. And when the 

 young corn of the harvest begins to grow, it is clothed in 

 spotted feathers ; and it always hates this place of Pal- 

 lene, and inhabits deserted forests and mountains. " 



5. Some birds dust themselves, and others bathe. Some 

 neither dust nor bathe. Those that do not fly, but live on 

 the ground, dust themselves, as the domestic fowl, partridge, 

 grouse, lark, and pheasant. Those birds which have 

 straight claws, and live near rivers, marshes, and the sea, 

 bathe themselves. Some, like the pigeon and sparrow, both 

 dust and bathe. Most of those with crooked claws do nei- 

 ther the one nor the other. This is their nature in these 

 matters. The act of breaking wind backwards is peculiar 

 to some birds, as the turtle. Such birds make a strong 

 motion with their rumps when they utter their voice. 



CHAPTER XXXVII. 



1. ANIMALS not only change their forms and dispositions at 

 particular ages and seasons, but also when castrated. All 

 animals that have testicles may be castrated. Birds and 

 oviparous quadrupeds have internal testicles near their loins. 

 In viviparous animals with feet, they are generally external, 

 though sometimes internal ; in all they are situated at the 

 extremity of the abdomen. Birds are castrated near the 

 rump, the part with which they touch the female in copu- 

 lation, for if they are burnt in that part two or three times 

 with irons after they are full grown, the comb turns yellow, 

 and they cease to crow, and no longer desire sexual inter- 

 course. If they are not full grown, these parts never reach 

 perfection. 



2. The same is the case with the human subject, for if a 

 boy is castrated, the hair that is produced after birth never 

 appears, nor does his voice change, but continues sharp ; 

 but if a full grown man is castrated, all the hair produced 



