UNSOLVED PROBLEMS. 157 



judge of the force of this fact it must be borne in mind how 

 readily dogs commit errors of identity, how easily they fail 

 to recognise their own loved masters under unusual circum- 

 stances for instance, as to mere dress. There are many in- 

 stances of dogs not knowing their masters when the latter 

 were simply nude as when bathing or had changed their 

 ordinary dress for a hunting or fancy costume, or had ap- 

 peared in the unexpected role of burglars or otherwise. The 

 marked antipathy to butchers, and the discovery of butchers 

 simply as such in any company and under any circumstances, 

 by certain dogs, is usually attributed to the use of their 

 keen powers of smell or scent ; but that this is the proper 

 explanation cannot be said yet to have been determined. 

 Other singular antipathies, the nature or causation of which 

 has also yet to be determined, include 



1. That of European dogs to negroes, according to Mon- 

 teiro. His own dog never got over this aversion, one that is 

 set down to the odour of the negro's skin, which is described 

 as abominable. But it may be due partly also, or altogether, 

 to mere colour. 



2. That of nearly related birds which * in their earlier 

 years .... are close companions and friends,' such as the 

 swift and chimney swallow. 



It may be by smell or hearing, but it may also be by some 

 means at present unknown, that the dog or cat, even when 

 blind or when vision is otherwise impossible, discovers the 

 approach or presence of friends or foes, masters or strangers. 

 I have myself repeatedly seen an old blind cat at once detect 

 the presence in a room of a domestic servant who was un- 

 kind to it, and seek safety from the dreaded kick apparently 

 by immediate flight or concealment. It was impossible for 

 me to determine from what I saw whether smell or hearing 

 was chiefly at work, whether the animal recognised the girl's 

 footfall or smelt her person or dress, nor had I the desirable 

 opportunity of putting the matter to the test by experimental 

 enquiry. Somewhat similar in character are 



1. The vague uneasiness felt and shown by the dog in 

 proximity to a master whose person is unseen, or whose pre- 

 sence is presumably otherwise unknown. 



