FOURTH WEEK] July 199 



when running before a hound may double back, and make 

 a close reconnaissance near his trail, sometimes passing in 

 full view without the hound's seeing him or stopping in 

 following out the full curve of the trail, so completely does 

 the wonderful power of smell absorb the entire attention 

 of the dog. 



Let us now turn to the oriole. As we might infer, the 

 nostrils incased in horn render the sense of smell of but 

 slight account. It is hard to tell how much a bird can 

 distinguish m this way probably only the odour of food 

 near at hand. However, when we examine the eye of our 

 bird, we see a sense organ of a very high order. Bright, 

 intelligent, full-circled, of great size compared to the bulk 

 of the skull, protected by three complete eyelids; we 

 realise that this must play an important part in the life 

 of the bird. There are, of course, many exceptions to such 

 a generalisation as this. For instance, many species of 

 sparrows are dull-coloured. We must remember that the 

 voice the calls and songs of birds is developed to a 

 high degree, and in many instances renders bright colour- 

 ing needless in attracting a mate or in locating a young 

 bird. 



As we have seen, the sense of smell is very highly 

 developed among four-footed animals, but to make this 

 efficient there must be something for it to act upon; and 

 in this connection we find some interesting facts of which, 

 outside of scientific books, little has been written. On 

 the entire body, birds have only one gland the oil gland 

 above the base of the tail, which supplies an unctuous 

 dressing for the feathers. Birds, therefore, have not the 



