HORSE ROX-VARIOLA EQUINA. 
31 
ing np the legs ; seen also on the muzzle, mouth and nose, groin 
and perineum, and in a few instances diffused over the shoulders 
and loins. In cattle it is almost invariably confined to the 
udder. 
Jenner, the great discoverer of vaccination, one of the most 
important advances in medicine, was of the opinion that cow-pox 
was often due to the accidental transmission of the virus of the 
horse to the udder of the cow from the hands of a milker who 
had been taking care of horses suffering from variola. 
Crusehman says: “ The horse-pox very probably can be 
inoculated upon the human subject with the same effect as vac¬ 
cinia, and the practice is objected to merely because horses have 
other kinds of sores upon the foot print which occasion disagree¬ 
able mistakes sometimes.” 
On this subject I might remark that both during the epizootic 
of this disease in 1877 and the present winter, I have invariably 
urged the grooms not to fear inoculation, as their being suscepti¬ 
ble to it indicated their susceptibility to small-pox, and that if 
they became inoculated it would in all probability protect them 
as surely as vaccination would. From observation in half a 
dozen cases of inoculation of grooms, four on the hand and two 
on the face, I am convinced that the results are identical with 
vaccination. Two or three days from the time of inoculation the 
part becomes red and slightly swollen, a sympathetic swelling 
also extending up the arm to the oxilla when in the hand, ac¬ 
companying which there is a slight fever. By the fourth day a 
single vesicle forms containing clear lymph, which enlarges till 
about the seventh day it attains a diameter of an eighth of an 
inch, and gradually becomes opaque. About the tenth day it is 
yellow, and the surrounding tissues are swollen and red. It now 
gradually begins to desiccate, beginning in the centre ; the scab 
thickens and dries and becomes of a dark brown color, and about 
the seventh day it is thrown off, leaving a scar similar in every 
respect to that seen from vaccination. 
With regard to the causes of this disease, it may be difficult to 
account for it. During a residence extending over seventeen 
years in Canada, I have only seen it twice, viz : in 1877 and dur- 
