, 1892-07-13
Texas cattle with ticks.
N. Carolina cattle without ticks.
Ticks scattered over the pasture.

4. TICKS scattered over tn0 pasture.
S. Soil taken from infested ". Caroline
pastures.
The results were confrrmatory of the prsyi-
GUS years conclusions. The first animal to
die was q northern beast in No. 4. NO diA-
ease appeared in No. S. over which the so1A
had been spread. In consequence of heavy
rain washing from No. 2. down into No. 5.
although q wide lane interviewed, ticks and
eggs were introduced therein and the north
ern cattle in it all died of the fever, ticks be.
ing found on their bodies in abundance.
The precise manner in which The disease
is caused is by no means clear. But 1t Is i'm
portant to note the fact connected with it's
incubation. Suppose that native and south
ern cattle are placed together on the same
pasture, it will take from forty to sixty days
for the disease to appear. After such APP
pearance fresh animals introduced may die
as soon as thirteen days after the exposure.
There seems to be but one inference to be
drawn from the observations and that is that
the presence of young tioks is directly asso-
dated with the appearance Of the disease. 1t
requires from 40 to so days for the mature
ticks to drop from their southern hosts and
the eggs they lay to hatch out After that there
is d constant supply Of young ticks until the
cold destroys them and the disease slackens
Off In other words the incubation pheno-
mena of the disease correspond with, the in
cubation phenomena Of the ticks.
The question was solved experimently in
the following manner Eggs laid by tloks
obtained from N. Carolina were laid on dry
leaves placed on moist soil and tended IN the
laboratory sill the young hatched out. The
period depended entirely upon the. tempera-
- ILL -.-u Gr@~o Ak lava ~ ~
to 40 in winter. These ticks were placed on
four separate animals. Two were kept in
stalls. and two were allowed to feed in a
patch on woodland with healthy cattle. OF
the four, died of Texas fever, with all the
usual symptoms The Others became very i'll
and though one recovered, his fellow had to
be killed. In both the protozoon was obser~
we'd in the blood, There was absolutely no
difference between the disease induced in these
cases. and that communicated in the ordinary
way by southern cattle. In from nine to
twelve days after the placing of the ticks, the
temperature of the animal rose considerably,
in one case as high as 1910.
The following case is appended
Sept. II. No. l44-Cow about 8 years old
Ticks Matched in the laboratory from eggs Of
N. Carolina ticks placed on the animal, blood
oorpuscles normal, So.
Sept. 24-Second lot of recently Matched
ticks applied.
Sept. 27.-Tomperature. 10loF.
Sept. 29.-Temp. 1862 Q, pulse st, rsspi.
ration %, oorpusoles reduced to 493.
Sept. 3O.-Temp. l07 o.
Oct, Temp. 10Y o.
Oct. Temp, l0+ Q
Got. 3.-Found dead.
Lungs only partly collapsed, traohea anti
bronchi filled with foam, Spleen very large,
soft weighing 4 lbs. 1oz., instead of about II
lbs::as usual. Liver weighs u lbs, enlarged,
yellowish on section, complete injection of the
intra.labolar bile oapillaries, bile dark, full OF
yellowish fakes. Kidneys much oouges ted.
Urine IN The bladder a deep port mine colour,
barely translucent in test tube, albuminous
preoipitate very abundant. Dense precipl-
tate with acetio acid (~baemoglobin).
In preparations Of the blood in this case,
some Of the . coorIpauus0less contained the parasites
in q contracted state, '1.6 to 2 nm in dismeT
ter. In the blood, spleen, fivers: and kidney
large bacili Of post norton growth. 1sppesgsdf
Such are invariably present when the ganiimnssAA
had dsizedd. early ia in tie night and is not exa4mipp-t
ed Until next day. They are never found in
the animals that are killed in q dying condla
ton 1t may Their, be considered proved that
Texas fever, or Red water, al we oall it, can
be produced By the action Of young ticks on
cattle not previously touched BY, them. 1t is
NOT . more ahstraction Of blood for the ticks