434 W. E. RITTER AND M. E. JOHNSON 
importance of exactness in the determination of external factors. 
So far these methods are admirable; but, it appears to us, it 
must be recognized that when exactness has gone thus far it has 
gone at best not more than half the way. Nothing less than equal 
exactness all along the line will do to fulfil the highest demands 
of physical science. 
Let one recall the degree of refinement with which physicists 
and chemists are measuring the phenomena with which they deal: 
the wave lengths and angles of refraction of light; the quantity 
of heat generated in chemical reactions; diffusion rates of gases 
and liquids; atomic weights and combining ratios, and innumer- 
able other things. Then let him compare these with the ridicu- 
lously crude quantitative determinations made in nearly all 
departments of biology. A few aspects of physiology, as for 
instance, the temperature of the human body; and a number of 
phases of the psychology of higher animals—reaction times, for 
example—have been brought under mensurational treatment 
comparable with the standards of exactness long demanded in 
physics. But the vast fields of morphology, of general physiol- 
ogy, of individual and race growth and decline, of propagation, 
of variation, of automatic and responsive action, etc., have hardly 
been touched quantitatively as physics and chemistry would 
understand this term. As yet we in biology have hardly heard 
of anything corresponding to physical constants, units of measure- 
ment, coefficients of change, etc. Yet will any one, fully alive 
to the spirit of modern physical science, venture to maintain 
that inorganic phenomena are so utterly different from organic, 
that conceptions and practices so enormously fruitful in the one 
realm are wholly inapplicable in the other? 
It is a significant fact that many biologists, the most ardent 
in defence of the so-called mechanistic or materialistic view of 
living things, are farthest away from, even most hostile to, the 
very methods for biology proper that have so largely made the 
physical sciences what they are. One looks in vain through num- 
bers of technical writings by biologists of this school for anything 
like exact, comprehensive accounts, either qualitative or quan- 
titative of organsims or parts of organisms, or even functions 
