LIVERPOOL MICRO. SOCIETY.—PRESIDENT’S ADDRESS. 59 
to itself, the result of chemical combination being a substance 
differing from any of its separate constituents. If an acid—say 
acetic, is brought into contact with an alkali—say potash, the two 
unite and a compound, acetate of potash, is formed, which differs 
materially from both the acid and the alkali; and if this compound 
is brought into contact with an acid for which the alkali has a 
stronger affinity than for acetic—say nitric, the alkali will leave the 
first and unite with the second acid, forming a new compound— 
nitrate of potash—quite different from either of its constituents ; 
and so we may go on through endless chemical combinations more 
or less simple, but in none of them is there any conversion of one 
substance into the other; the resulting compound, as I have 
already said, invariably differing from its constituents. Chemists 
have rather recently been able to produce in their laboratories 
compounds which had hitherto been supposed to be produced only 
by living bodies, but these compounds are non-living. No chemist 
has been able, or probably ever will be able, to manufacture a 
single particle of living matter, and the fact remains that to proto- 
plasm alone belongs this power. We cannot tell how this trans- 
mutation is effected in the absence of mouth, stomach, secretory 
organs, or indeed organs of any kind, there being nothing from 
which we can obtain any information, or which will give us any 
hint as to the modus operandi. 
There is another point in connection with assimilation to 
which I may briefly allude, and that is the power of sensation 
possessed by protoplasm. On being touched by a particle of 
suitable food the soft matter of an amceba flows round and 
engulphs it with a view to assimilation. Now, this action of 
the protoplasm, for of such the amoeba entirely consists, indicates 
a power of receiving impressions from without and acting upon 
them ; for it is evident that, were it not so, the touch of an 
external object would not be responded to, and the protoplasm 
would remain inert. It is indeed asserted that contact 1s not 
always necessary, but that a particle of food in the neighbourhood 
of an ameceba can exercise a stimulating effect upon it, with the 
result of pseudopodia being thrust out for its appropriation. This, 
however, is perhaps a little doubtful ; and, though my own observa- 
tions have in some cases seemed to confirm it, I am not satisfied, 
and think the verdict at present must be non-proven. But how- 
ever this may be, the fact of protoplasm receiving and responding 
to impressions from external objects remains ; and we thus have it, 
without nerves or other apparent organisation, exercising a power 
which in higher animals requires a nervous system more or less 
elaborate, which again implies something more than is visible even 
with the microscope. 
Let us now pass to another power, viz., that of motion, z.¢. its 
