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CONTRIBUTIONS TO THE PATHOLOGY AND 
itself, or upon a favourably exciting cause ; or upon the two acting 
in combination. Setting aside, however, considerations of so ge- 
neral a character, I may enumerate as predisposing to purpura, in 
particular, such affections as chronic cough ; or rather, that local or 
general morbid state of the organism, or part of the organism, which 
is productive of chronic cough ; secondly, that state of the vital 
energies denominated as “ naturally weak thirdly, chronic dis- 
ease of the fauces; fourthly, that morbid tendency within the 
system, which, from the action of very slight exciting causes, ad- 
mits of the frequent development of colic, or other forms of mor- 
bid irritation of the bowels ; fifthly, the keeping of horses in 
damp, unclean, and ill ventilated stables ; and, lastly, two or more 
of these causes acting in combination. Cases 11, IV, and V, are 
examples as to the predisposing nature of chronic cough, colic, 
and of the naturally weak constitution. With respect, again, to 
chronic disease of the fauces, I may mention that I once attended 
upon a draught horse affected with purpura, which for a long time 
previously had had disease of the fauces of a very obscure nature ; 
the animal, however, ultimately recovered after more than six 
months’ duration of the disease purpura. 
Exciting Causes. — As immediate or exciting causes I may par- 
ticularise catarrhal or epidemic diseases, such as laryngitis, scarlet 
fever, and exposure to wet and cold during the convalescent stage 
of any of the above diseases. 
Varieties of Purpura . — Purpura, with reference to its manifesta- 
tion in the human being, is divided, says Hooper, “into the five 
following species : — viz. purpura simplex, purpura hcemorrhagica, 
purpura urticans, purpura senilis, and purpura contagiosa .” The 
second variety, however, or purpura hcemorrhagica, is the one 
which the veterinarian has usually to deal with; and it is mani- 
fested, as John Field very truly observes, in the acute and sub- 
acute conditions. Of the acute, Case IV, and of the subacute, 
Case V, are examples of each condition respectively. The peculiar 
manner in which this disease invaded the animal in Case V is 
worthy of remark; the real disease was masked throughout. I 
regarded the case, at its onset, as being one of irritation of the 
bowels, and treated it accordingly ; while the loss of motor power 
I considered as an anomaly which time might enable me to unravel, 
and which it certainly did, but not in the manner I anticipated. 
The facts made known by the post-mortem prove, in my opinion, 
that the disease must have been going on for some time ; most 
probably the purpura supervened upon the disappearance of the 
pleuritis. The loss of the motor power of the hind limbs was 
clearly accounted for from the state of the psose muscles; while 
