THE PRESIDENT'S ADDRESS. 
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mathematical lines, modifiable at pleasure by the introduction of 
new elements into the surroundings, devoid of internal movement 
and absorption of new matter from without. It is, in reality, a 
minute pack of bricks. The other is mobile, active throughout 
its entire substance, moves towards other substances, transmutes 
them by a power very unlike mechanism into itself, and can only 
arise from its own kind. It is true, we do not know why in a 
certain crystal the particles should always lie at a given angle in 
relation one to the other ; but we do know that the mutual action 
is external, and can be varied at pleasure by the chemist's skill. 
There is a singular remark of Lester's — no mean authority — which, 
though not made in reference to living matter, as contrasted with 
crystals, serves well to indicate the enormous remove of the one 
from the other, and to imply, at least, the high probability of 
some unique power or elective agency. He says : " We know 
that it is one of the chief peculiarities of living structures that 
they possess extraordinary powers of effecting chemical changes 
in the materials in their vicinity, out of all proportion to their 
energy as mere chemical compounds.' ' 6 
I have hitherto explained the proofs which the mechanical 
school adduce in support of the hypothesis suggested by the 
Principle of Continuity ; namely, that living matter in the first 
instance arose out of some prior condition of things, and we 
have noticed what can be said on the other side as to the value of. 
those proofs. But there are a few valiant advocates of the 
hypothesis, such as Buchner and Haeckel, who even go so far as to 
assert that Life noiv can be produced out of inorganic conditions. 
As a rule Naturalists consider that the doctrine of Biogenesis, 
ovu?n ex ovo, alone applies to life now, either in the way of 
Bioparadosis, transmission; or Biocaenosis, renewal; or Biodiaeresis, 
fission ; or Biocrasis, fusion. It is probable that Aristotle and 
Lucretius held the view that, in addition to Biogenesis, Life still 
occasionally sprang from non-living matter. In our own country 
vulgar belief, even in the year 1638, had connected the appearance 
of small vermin with changes in the inorganic world ; and in the 
eighteenth century the expression " Spontaneous Generation " was 
invented to indicate the nature of the change. There is much in 
the expression that is fascinating to a certain order of mind ; and 
the frequency with which animal Life appears to spring in 
6 Quoted by Tyndall in Fragments of Science, p. 148. 
