656 ON THE EXTERNAL CAUSES OF DISEASE. 
at the time of its development, forty-nine were dead, and fifteen 
diseased, eight of the latter were destroyed, and the examination 
of them served to explain the nature of the disease ; for on com¬ 
paring the observations which he made on the carcasses of the 
dead with the symptoms and character of disease observable in 
the living patients, he was assured the primitive alteration, the 
essential maladp, teas in the blood, which, whether taken from the 
dead or living animal, covered his hands without reddening them, 
and either did not coagulate, or formed a mass of a dirty grey 
colour, and contained a very small portion of fibrine, which w^as 
easily proved by analysis. 
These alterations were yet more perceptible in the horses that 
had been diseased for some time. There was so little cohesion 
between the organic elements of the blood, that, even during the 
life of the animal, the fibrous filaments separated from the liquid 
W’henever it w^as agitated, although in the slightest degree^. 
A’striking fact shewing the relations between the composition 
of the blood in the state of disease, and the secretions \vhich de¬ 
pend upon it, was discovered by Chevreul. Children are subject 
to a disease characterized by induration of the cellular tissue : on 
analyzing the fluid secreted by this tissue, he found that it con¬ 
tained a substance which coagulates whilst cold. He has also 
recognized its existence in the blood of the same patients, and 
this in great proportion. It is the same with the colouring matter 
of jaundice, which frequently accompanies this disease. Thus, 
morbid secretions ai^3 connected with the constitution of the 
blood by the co-existence of the same principles in this and the 
other fluids. 
On making an analysis of the blood, we discover it to contain 
a variety of particles, differing in bulk, weight, figure, and tena¬ 
city— some watery, others inflammable, and most of them greatly 
inclined to putrefaction, and of an alkaline nature. Blood in a 
sound state, not injured by putrefaction, or by too violent a de¬ 
gree of heat, is neither alkaline nor acid, but mild and gelatinous, 
and a little saltish to the taste; yet in some diseases it is very 
* See Veterinarian, vol. v. 
