264 MORBID BODILY CONDITIONS 



nervous disturbance is to be found in tremor or trembling, 

 either general of the whole body or only of special portions 

 thereof, as of the lips or teeth. Tremor varies in its intensity 

 and duration, the mildest form and degree consisting of the 

 mere transient nostril or lip-quiver in the high-bred, restless 

 horse, or the teeth-chattering of apes and monkeys. Alarm, 

 fear, or fright produces general tremor, trembling, or quiver- 

 ing in the young turkey and in various small cage birds. 

 The bot-fly in cattle begets a terror that is expressed by 

 general tremor (Figuier). Tremor is the result of restrained 

 ardour in the harrier that is prevented by the leash from 

 following the hare (Pierquin) . Tremor of the leashed deer- 

 hound in presence or sight of a deer arises probably from 

 a combination of feelings or emotions, ardour or eagerness, 

 impatience, expectation, and general mental excitement. 

 Tremor in its various degrees is producible by different 

 mental causes, of which the principal are 



1. Fear, fright, or terror in all its degrees. 



2. Excitement, ardour, eagerness, impetuosity, impatience, 

 longing, expectation also of all degrees. 



3. Happiness, physical and mental sense of enjoyment. 



4. Mental suffering of all kinds. 



Here again, as in so many other instances, the same or 

 similar results are producible by purely physical causes, or 

 by influences conjointly and variously bodily and mental ; 

 and it is frequently difficult or impossible to distinguish 

 the psychical from the physical causes, or the degree in 

 which the one or the other kind of influence has been ope- 

 rative in a given result. 



The liability to tremor or general tremulousness or shaking 

 of limbs is commonly spoken of as shaken nerves ; and no 

 doubt there is for the moment, and it may be more perma- 

 nently, a generally disordered nervous sensibility. Tremu- 

 lousness, indeed, is apt to occur in proportion to the nervous 

 sensitiveness of animals, and hence it is commonest in high- 

 bred dogs or horses endowed with extreme muscular and 

 nervous irritability. 



The most familiar instances of tremor from fear occur 

 in the horse for instance, in presence of the lion or of any 



