6 PRESIDENT’S ADDRESS. 
The fact that the formation of such a conception is only possible 
in connection with life, and that the growth and elaboration of the 
conception has only been possible as the result of the most complex 
processes of life in the most complex of living organisms, has doubtless 
led to a belief in the identity of life with soul. But unless the use of 
the expression ‘soul’ is extended to a degree which would deprive 
it of all special significance, the distinction between these terms must 
be strictly maintained. For the problems of life are essentially 
problems of matter; we cannot conceive of life in the 
Problems of scientific sense as existing apart from matter. The 
tc prob- phenomena of life are investigated, and can only be inves- 
matter. tigated, by the same methods as all other phenomena of 
matter, and the general results of such investigations tend 
to show that living beings are governed by laws identical with those 
which govern inanimate matter. The more we study the manifestations 
of life the more we become convinced of the truth of this statement and 
the less we are disposed to call in the aid of a special and unknown form 
of energy to explain those manifestations. 
The most obvious manifestation of life is ‘ spontaneous ’ movement. 
We see a man, a dog, a bird move, and we know that they are alive. 
We place a drop of pond water under the microscope, and 
Phenomena see numberless particles rapidly moving within it; we 
senate. of affirm that it swarms with ‘ life.” We notice a small mass 
ment. of clear slime changing its shape, throwing out projections 
of its structureless substance, creeping from one part of 
the field of the microscope to another. We recognise that the slime 
is living; we give it a name—Ameba limaz—the slug amceba. We 
observe similar movements in individual cells of our own body; in 
the white corpuscles of our blood, in connective tissue cells, in growing 
nerve cells, in young cells everywhere. We denote the similarity 
between these movements and those of the amceba by employing the 
descriptive term ‘ amceboid ’ for both. We regard such movements as 
indicative of the possession of ‘ life’; nothing seems more justifiable 
than such an inference. 
But physicists? show us movements of a precisely similar charac- 
ter in substances which no one by any stretch of imagination can 
oa regard as living; movements of oil drops, of organic and 
melty ot inorganic mixtures, even of mercury globules, which are 
living and indistinguishable in their character from those of the 
sa hig living organisms we have been studying: movements which 
; can only be described by the same term ameeboid, yet 
obviously produced as the result of purely physical and chemical 
reactions causing changes in surface tension of the fluids under exami- 
7G. Quincke, Annal. d. Physik u. Chem. 1870 and 1888. 
