the force of criticism
has been recognised even by those occupying a convinced mechanical point
of view. He subjects all the different theories which attempt to explain
the chief vital phenomena in mechanical terms to a long and exhaustive
examination. The theories of the organism as a thermodynamic engine,
osmotic theories, theories of ferments, interpretations in terms of
electro-dynamics and molecular-physics--are all examined (chap. iv.); and
the failure of all these hypotheses, notwithstanding the enormous amount
of ingenuity expended in their construction, is summed up in an emphatic
"_Ignoramus_." "The failure is a striking one," and it is frankly admitted
that, in strong contrast to the earlier mood of confident hope, there now
prevails a mood of resignation in regard to the mechanical-experimental
investigation of the living organism, and that even specialists of the
first rank are finding that they have to reckon again seriously with vital
force. This breakdown and these admissions do not exactly tend to
prejudice us in favour of the author's own attempt to substantiate new
mechanical theories.

In the comprehensive text-book of physiological chemistry by R.
Neumeister, the mechanical standpoint seemed to be adhered to as the
ideal. But the same writer forsakes it entirely, and disputes it
energetically in his most recent work, "Betrachtungen ueber das Wesen der
Lebenserscheinungen"(84) ("Considerations as to the Nature of Vital
Phenomena"). He passes over all the larger problems, such as those of
development, inheritance, regeneration, and confines himself in the main
to the physiological functions of protoplasm, especially to those of the
absorption of food and metabolism. And he shows, by means of
illustrations, in part Bunge's, in part his own, and in close sympathy
with Wundt's views, that even these vital phenomena cannot possibly be
explained in terms of chemical affinity, physical osmosis, and the like.
In processes of selection (such as, for instance, the excretion of urea
and the retention of sugar in the blood), the "aim is obvious, but the
causes cannot be recognised." Psychical processes play a certain part in
the functions of protoplasm in the form of qualitative and quantitative
sensitiveness. All the mechanical processes in living organisms are
initiated and directed by psychical processes. Physical, chemical and
mechanical laws are perfectly valid, but they are not absolutely dominant.
Living