ZOOLOGICAL PARKS AND AQUARIUMS 



917 



ceptible to the illnesses of humans, especially the diseases of the respiratory 

 tract. It is therefore desirable that these animals be kept behind glass, if 

 possible, to avoid contact with visitors suffering from colds or like con- 

 ditions, and also to prevent feeding by the public. A view of the interior 

 of the monkey house at the Philadelphia Zoo as shown in Plate 366 illus- 

 trates this method of protection. Another feature of the greatest impor- 

 tance in the construction of monkey houses, so far as the welfare of the 

 animals is concerned, is the outside enclosures as shown in Plate 367. These 

 outside cages are available to the animals at all times and are controlled 

 by swinging doors which are operated by the animals themselves, so that 

 they may go in or out at will. 



3. Service structures. Service structures are of two types, (i) those 

 structures used by the management in the conduct of the zoo; (2) those 

 structures provided for the comfort and convenience of the visiting public. 

 The first group comprises such structures as gate house or houses at those 

 zoos surrounded by a fence and to which an admission fee is charged, 

 administration building, kitchen for the preparation of food for those ani- 



PLATE No. 367 

 OUTSIDE ENCLOSURES FOR MONKEYS, PHILADELPHIA ZOOLOGICAL GARDEN 



