188 ANALYTIC PHYSIOLOGY. 
any other series of physical facts. The most for- 
midable difficulties which encompass Physiology, — 
are the multitudinous changes which the Vital 
Force undergoes from contingent circumstances ; 
and to detect the nice differences of these changes, 
forms the essential qualification of the Physician. 
Since I wrote the article on Animal Heat, I 
have seen a curious illustration of the relative 
effects of the motion of the blood and its contact 
with the nerves. John Lucas, aged 78, has been 
for some months under the treatment of Dr. Sillar 
and Mr. M‘Donald of the Liverpool Dispensary, 
who had the goodness to call my attention. to his 
peculiar case. ‘The disease is a hypertrophy and 
dilatation of the left ventricle of the heart, 
which contracts 31 times in the minute, and the 
heat under the tongue is 96°. The pulse of his 
wife, who is 74 years old, is 70 per minute, and 
the heat under the tongue 98°. The difference 
of 39 pulsations in these aged persons, makes 
only a difference of two degrees in their animal 
heat. 
The existence of a contractile power in the 
soft fibres of the body is universally admitted in 
the present state of Physiology ; in the foregoing 
pages, I have proved, by a series of arguments 
and experiments, that there is also an expansive 
power which pervades the fibrous texture of the 
body. The pressure or ligature of a nerve de- 


