DIFFERENTIAL DIAGNOSIS 153 
is ‘so marked that the animal is nothing -but ‘a weak 
skeleton; there are no ocular or nasal discharges; ‘and 
none of the typical nervous symptoms of distemper. ’:-’ ~ 
Where the investigator fails to demonstrate tberéle 
bacilli in any. discharges or serous fluids, diagnosis may 
be attempted by. applying the “tuberculin test,” pré- 
ferably in the morning, and noting the changes of ‘tem- 
perature hourly during the day, and if possible until 
twenty-four hours have elapsed. The dose of tuberculin 
for a dog is $ to 1 cubic centimetre injected subcu- 
taneously inside the thigh. The results, however, are 
not always reliable, and perhaps a better and more con- 
venient method of testing is by the use of ophthalmic 
tuberculin, wherein from one to two drops of this 
medium are brought in contact with the conjunctival sac. 
If the animal is tuberculous a reaction will be manifest 
- in from seven to twelve hours, consisting of the develop- 
ment of conjunctivitis with profuse lachrymation and pus 
formation. 
Epilepsy.—The causes of true epilepsy appear to be so 
far unknown, and no lesions have been discovered in the 
brain to account for it. It is believed to be hereditary, 
and may occur at any period of life. True epilepsy is 
frequently confounded with the symptomatic — variety 
arising from wasting diseases, and it would be avery 
difficult matter indeed to differentiate between the 
epileptiform convulsions associated with distemper -and 
those pertaining to idiopathic epilepsy. The former, how- 
ever, are usually much more acute and are accompanied 
by other recognised distemper symptoms, the develop- 
ment of which must be our guide in. diagnosis. 
Rabies.—The symptoms of cerebral. irritation com- 
plicating distemiper-have frequently .been. mistaken for 
rabies, and’ many dogs have in the-past been sacrificed 
as rabid when suffering only..from epilepsy. 
