PHYSIOGNOMY OF DISEASE. 175 



bite is not peculiar to rabies ; that biting, is not exhibited by 

 every rabid animal ; and that every biting animal is not neces- 

 sarily rabid. Biting has, therefore, no symptomatic or diagnos- 

 tic value per se (Pierquin), a fact that ought to be comforting to 

 those timorous people who regard every biting dog as neces- 

 sarily ( mad ' or rabid. Too frequently this tendency to bite 

 is the direct result of man's ill-usage, or of the fretfulness 

 which such ill-usage engenders. 



But it is not the less to be regarded on that account. 

 For whatever be the cause or origin of the habit or action, 

 biting by the dog is at all times an important symptom, or, 

 a vice, in itself one fraught with possible danger to man, in 

 so far as the bite of a merely angry or furious, non-rabietic 

 dog has been known, or alleged, to produce hydrophobia in 

 man (Parkinson). There is nothing either impossible or 

 improbable in the alleged occurrence from such a cause of so 

 serious a mishap, because the bite of man himself, or other 

 animals, in fury or mania not in a state of rabies is 

 sometimes fatal in or to other men or animals. The bite of 

 man himself, though it does not here quite appear whether 

 at the time he was hydrophobic, is said to have produced 

 hydrophobia in other men (Pierquin). The salivary secre- 

 tion both of man and other animals under rage or mania, 

 which may be regarded practically as merely different de- 

 grees of what is essentially the same condition, would appear 

 to be, or to become, diseased, poisonous, and virulent 'when 

 inoculated into or in other men or animals ; that is if it be 

 true, as Pierquin asserts, that a bite in either of the mental 

 conditions mentioned, and whether by man or other animals, 

 may lead to tetanus or convulsions as well as hydrophobia. 



What has been called in the carnivora the biting ( in- 

 stinct ' becomes strongly developed in various forms of 

 insanity in them (Pierquin). But biting may appear under 

 circumstances of disease or in captivity in animals in which 

 it is not a natural aptitude, e.g., in rabid sheep (Pierquin). 

 And in such cases of course it has a special diagnostic and 

 prognostic significance, exhibited as it is only under abnor- 

 mal conditions of mind and body. 



In the horse, according to Youatt, crib-biting may arise 



