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Scientific Memoirs by
rated data are worthy of close attention. Mr. Steel has published three separate
accounts, with charts, of inoculated mules and one of the pony, which on co
m - p a r i s o n w i t h o t h e r s o f t h e n a t u r a l m u l e - d i s e a s e a p p e a r s o m u c h a l i k e a s , i n m y
opinion, to quite justify his statement that the "surra" blood-infection with all
its attendants can be readily, exactly, and exclusively reproduced at will. I am
assured that adequate precautions were taken to ensure the absence of a natural
acquirement of the disease in these several instances, which therefore, along with
Dr. Evans' experiments, will serve to establish a truly fundamental datum.
To myself these observations were of particular interest because of the
aggregate clinical and pathological facts embodied in them demonstrating, further,
a striking similarity to the phenomena of the spirillum-infection with its attend-
ants as seen in the human subject. This similarity Mr. Steel has the credit of
first clearly making evident, whether or not in veterinary medicine his proposed
cognomen of "equine relapsing fever" displace the indigenous term "surra
" : b r i e f l y , i t c o n s i s t s ( a s r e g a r d s i n o c u l a t e d c a s e s ) i n t h e d e f i n e d a n d b u t l i t t l e
shorter incubation-period of 4—7 days, with no marked general symptoms and no
visible blood-contamination; then follows a succession of pronounced and de
-fined pyretic, and apyretic (incubatory) periods, of which 2 to 6 are shown in
the charts, and during which characteristic signsof illness and blood-tainting
regularly alternate with abatement of symptoms and disappearance of the
hæmatozoon: after death the lesions found, so far as I perceive, being solely
those of blood-deterioration without the marks of local inflammation or other
organic processes, either primary or in themselves sufficiently marked to account
for decease. The differences here, which I note, concern details in the course
of the pyretic events; these in 3 of the cases being, if equally pronounced, hardly
so defined ( e.g. , rigors and sweats not named) or so clearly separated by
apyrexial days, as is usual in the human disease—the point not however be-
ing wholly material, since fatal cases of relapsing fever and other speci-
fic infections of man are very apt to be irregular in their course: in the
longest surviving of Mr. Steel's mules, where death occurred from an
inci-dental internal embolism, the relapses were better marked, and from this
instance is it learnt that the equine infection manifests no such tendency
to decline by a deferring and shortening of the febrile attacks, as is manifested
in the human infection; thus the mule's series shows a succession of febrile
events lasting 7, 3, 4, 3, 4, 6 days, with apyretic intervals of a much shorter and
not lengthening succession of 3, 2, 2, 3, 2 days duration: add to these data
the commonly larger number of relapses (17 have been counted), and it will
become evident that the relapsing fever of equines is, comparatively, much the
more prolonged, intense, and intrinsically exhausting; indeed, so far from
possessing a spontaneously abating tendency, once supervening it never departs
until life itself ceases, and this, happily, is not the case with the spirillum-fever