67
hand, one can readily lift it up from the subcutaneous structure, proving that it
only involves the skin. A point of great interest, and a symptom of the greatest
clinical value occurs at the time of the organism leaving the seat of the swelling—
for the hæmatozoon has been proved, as in Horse No. VIII, to be present in the
fluid of the tumour three days after inoculation, and two days before being dis-
covered in the blood of the general circulation ; and in the case of Horse No. LIV,
twenty-four hour's before its first appearance in the blood,—in that the raised
tumour, which was previously tense, and so tender that the animal flinched
whenever touched, now suddenly becomes soft and flaccid, and manipulation of
the parts can be carried on, with little or no notice being taken by the inoculated
animal.
It will therefore be recognized, that from the time of inoculation until the
organism leaves the tumour for the general circulation, or in other words during
the latent period of inoculation, this disease is purely a localized affection, and
can therefore be treated, either by excision, or by the injection of antiseptics at
the seat of inoculation.
In one case only out of twenty-two, which contracted the disease by experi-
mental means, was the swelling absent from the seat of inoculation ; but in this
from first to last, during a period of nine days, no swelling or thickening of the
integument could be felt. The shortest time noted in horses during which the
swelling attained its maximum, and commenced to decrease in size was ninety-
six hours, and the longest twelve days, the average length of twenty-one cases
being 6.7 days. Within a very few days after the appearance of the hæmatozoon
in the blood, the tumour has usually decreased considerably in size, and after
a fortnight, only a slight thickening of the skin can be noticed on careful examin-
ation of the part.
3. The Temperature.—In the following, for the sake of description, the
peculiarities met with in the temperature will be dealt with—
(i) During the latent period.
(ii) Prom the discovery of the hæmatozoon in the blood until death.
(i) Temperature during the latent period.—Unfortunately we have no
records dealing with the temperature of animals during the incubative
period, in naturally contracted cases of Surra. We can, however, easily
conceive the reason for this want, knowing, as we do, the insidious
nature of the onset of the disease, and the difficulty there is in deciding
when any particular animal was exposed to the contagium. By ex-
perimental means, however, we are enabled to obtain an insight into
this question, and on studying the charts presented with the following
cases, it will be found, that the thermometric records present consider-
able variations, in that several different types of temperature curves
will be observed during the above-mentioned period.
In one set of cases the temperature remains low for a few days, and then
commences to rise, the morning and evening reading being about half
a degree Centigrade higher than that of the day preceding, but there
being a temporary arrest or remission of 1.5 to 2°C. in the morning.—
Vide Charts—Cases XXXVIII, LIV.
In a second series of cases, the curve delineated by the temperature read-
ings, presents for a varying period a diurnal variation, in some cases
showing well-marked intermissions (Vide case XXX), in others hardly
amounting to a remission ; and these are followed by a sudden rise of
temperature in a few, just previous to, or in the majority of cases
subsequent to, the appearance of the organism in the blood—No. XX,
XXIX, XL, XIII.
In a third series, the thermometer registers a normal or even subnormal
temperature, from the time of inoculation until the appearance of the
organism in the blood, and this condition has occasionally been observ-
ed to persist after the discovery of the hæmatozoon. Vide charts—
Cases No. XXVII, XXXVII, XLI.
In a fourth series, the temperature commences to rise, either gradually or
suddenly after inoculation, and attains a maximum varying from