70 



ON THE SEI^SE OE SMELL IN DOGS. 



my uncovered head above the level of the surrounding fields. 

 When she was led within two hundred yards of the place, she 

 instantly perceived my odour, and ran in a straight line to where I 

 had then ducked my head, so that she should receive no assistance 

 from her sense of sight. This experiment shows that, in the 

 absence of wind, the odour of my head (and no doubt, in a lesser 

 degree, that of my body) liad diffused itself through the air in all 

 directions, and in an amount sufficient to enable the setter to 

 recognize it as my odour at a distance of two hundred yards. 



Trom the above experiments I conclude that this bitch distin- 

 guishes my trail from that of all others by the peculiar smell of my 

 boots (1 to 6), and not by the peculiar smell of my feet (8 to 11). 

 No doubt the smell which she recognizes as belonging distinctively 

 to my trail is communicated to the boots by the exudations from 

 my feet ; but these exudations require to be combined with shoe- 

 leather before they are recognized by her. Probably, however, 

 if I had always been accustomed to shoot without boots or 

 stockings, she would have learnt to associate with me a trail made 

 by my bare feet. The experiments further show that although a 

 few square millimetres of the surface of one boot is amply 

 sufficient to make a trail which the animal can recognize as mine, 

 the scent is not able to penetrate a single layer of brown paper 

 (10). furthermore, it would appear that in following a trail 

 this bitch is ready at any moment -to be guided by inference as 

 well as perception, and that the act of inference is instantaneous 

 (12 and 13 as compared with 2, 8, and 11). Lastly, the experi- 

 ments show that not only the feet (as these affect the boots), but 

 likewise the whole body of a man exhales a peculiar or individual 

 odour, which a dog can recognize as that of his master amid a 

 crowd of other persons (15) ; that the individual quality of this 

 odour can be recognized at great distances to windward (15), 

 or, in calm weather, at great distances in any direction (16) ; 

 and that it does not admit of being overcome by the strong smell 

 of aniseed (14), or by that of many other footprints (4). 



