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ELISHA MITCHELL SCIENTIFIC SOCIETY. ° 71 
failure. ‘The best of modern thought agrees with him in 
one sense at least when he says: 
‘‘And life itself is but a part of death.”’ 
Death he believes comes from some shock which shat- 
ters and destroys the union of the atoms. The shock 
theory of fermentation and decay was vigorously main- 
tained and defended duriug the frst half of this century. 
Then when some greater shock a life assails 
Than Nature can support, sudden all sense 
Of mind and body is confused and stunned. 
The ordering of elements dissolved, 
Their bond of union snapped, the silver cord 
Is loosed, the vital tide turned back, and life 
With all its elements dispersed. But what 
Can blows do more than shatter and dissolve 
What once was joined? 
: Book II p. 108 
Liebig in 1852 reasoned that contagion was due to 
gaseous matter in’a state of decomposition. Disease is 
excited by contagion. According to the ‘“‘law of La 
Place and Berthollet: A molecule set in motion by any 
power can impart its own motion to another molecule 
with which it may be in contact. The motion of these 
decomposing molecules is transmitted to the blood and 
if decomposition there is not overcome it proceeds over 
the entire body.’’ ‘This reads almost as strangely as 
the words of Lucretius. It is only just to Liebig to add 
that he acknowledged his errors afterwards and accept- 
ed the theories of Pasteur and Schiitzenberger. 
Lucretius’ theory of contagion would sound very much 
like the modern germ theory if only his seeds were en- 
dewed with life. 
First, then the air teems, as I’ve taught, with seeds 
Diverse, some favoring life, but many more 
Fraught with disease and death; chance gathered, these 
Infect the sky, malignant make the air. 
Lucretius has anticipated the recent address of Sir 
