ON INCREMENT OF ANIMAL HEAT. 
421 
terial system, and especially of the extreme or terminal parts 
of the arterial vessels : the vessels resist; there is obstruction 
—congestion some would call it—and, as a necessary conse¬ 
quence, there is diminished excretion or secretion from the 
excreting and secreting surfaces. On this follows that accu¬ 
mulation of water in the blood itself, to which I called your 
earnest attention in my last lecture. Upon the accumula¬ 
tion of water follows that tension of the arterial pulse, which 
runs so steadily with suppressed secretion. Upon this often 
follows rapid accumulation of fluid in serous cavities or exu¬ 
dation of fluid in the least resistent organs—the cellular 
exudations of local upon general inflammation. 
At this stage there may be another series of symptoms sud¬ 
denly developed : as if the rapidly speeding engine had been 
suddenly reversed, there may be slower motion, gradually fall¬ 
ing temperature and collapse. The change indicates in nearly 
every instance that there has been separation of fibrine in the 
heart. The separation has stopped or arrested the current of 
blood at the main, and, virtually, all is over. In the human 
subject we recognise by external signs this condition con¬ 
stantly ; in the inferior animal we produce it synthetically, and 
determine it with precision. Here, in illustration, is the dead 
body of a cat. In this animal there was, during life, an induced 
increment of heat, or fever. The fever progressed until the mean 
temperature of the animal had reached an increment of nearly 
10 degrees; then the animal began to sink.^^ She might 
have struggled on hopelessly for hours, as human bodies do, 
but we could in her case put her quickly to death, in sleep, 
by making her inhale the vapour of ether. We did so, and 
at once we laid bare and laid open the heart. See what has 
happened. The right cavities are almost filled with a firm 
separation of fibrine. Of the many similar specimens from 
the human subject which have been before us there is not 
one specimen more distinct than the specimen in our hands. 
If, in your leisure, you will turn to my work on the coagu¬ 
lation of the blood, you will find that, in the year 1854, I 
performed the very same experiment I have performed at the 
present moment. Then, however, I used pure oxygen for 
the inhalation, and my idea at the time was that the inhala¬ 
tion of oxygen was the cause of an increase of fibrine, for I was 
ignorant of the direct and potent effect of simple increase of 
animal temperature. Now, with a better knowledge, I know 
that the oxygen played only a secondary part; that, in fact, 
pure oxygen is not essential; that no more and no less is 
required than increase of heat within the organism. 
If the increment of animal lieat be induced with such 
