INAUGURAL ADDRESS 
ON 
The DEFINITION OF LIFE as affected by the 
PROTOPLASMICG THEORY. 
By Joun Dryspauz, M.D., F.R.M.S., Presipent. 
[Read 29th October, 1887.] 
INTRODUCTORY AND HISTORICAL. 
CoRRECT definition is the offspring of true knowledge and 
correct thinking, while it is the parent of farther correct 
thinking and the advance of knowledge. In no depart- 
ment of science are correct definition and precision in 
terms of more importance than in that dealing with life. 
The first question here is whether the word is to be 
applied to the characteristic actions of living beings, or to 
an actual or supposed thing presumed to be the cause of 
those actions. ‘“‘That lfe is an entity or substance, 
material or immaterial, resident in a certain aggregation 
of matter and the cause both of its organisation and of 
the characteristic actions which it afterwards performs, 
is the oldest opinion on the subject,’ and one that has 
descended to the present time, expressed by a variety of 
names, some of which are still in vogue, such as the Vital 
Spark, the Vital Spirit, and the Vital Principle. This view 
was hardly questioned till 1780, when John Brown wrote his 
celebrated ‘‘ Klementa Medicine,’’ wherein the existence 
of any such entity was denied, and life was said to consist 
merely in a series of actions performed by organic beings, 
resulting from the operation of certain exciting powers 
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