144 “ Handling Evidence of Growth and Change .” 
Yet with “Witness” and Mr. McLean I would strongly 
deprecate the relegation of morphology to specialised advanced 
courses. Even a crude picture of the evolution of plants stimulates 
the imagination of many students for whom physiology, at least as 
commonly taught, means little but a dreary waste of formulae and 
glass apparatus! 
Phylogeny is after all the growth of the race. To follow in 
imagination the course of creation must ever make an intense 
appeal. The trouble is that phylogeny has become an idee fixe , 
to the exclusion of other points of view—exclusive, because it has 
been a narrow phylogeny, based almost solely on the comparison 
of adult structures. Even phylogeny will be revivified when a 
synthesis of morphology with physiology (in the widest sense) is 
effected, and plants are dealt with as the concrete living beings 
that they are. 
Physiology is often anything but the study of plants as living 
beings, and is justly criticised as suffering at present from a sharp 
isolation. If physiology were to oust morphology its isolation 
would be no less. 
The teaching of physiology has its own special difficulties. 
One reason why morphology holds so strong a position is that it 
is self contained. A student can be introduced to it without any 
previous knowledge of science; the facts can be directly observed 
and the processes by which generalisation are reached readily 
illustrated. Physiology in the more restricted sense demands on the 
other hand a sound knowledge of mechanics, physics and chemistry, 
including physical chemistry. Taking facts of structure determined 
by observation and facts experimentally established regarding 
nutritive and other metabolic processes of plant life, it seeks to 
describe them in terms of the physical and chemical principles 
already available. In the nature of the case this process is 
enormously complex and difficult. With students who lack a 
sound preliminary training in chemistry and physics the teacher 
must provide the necessary knowledge as he proceeds and restrict 
his field within very narrow limits. 
This sort of specialised physiology is not, however, essential 
to a revivifying of elementary teaching. How the physiological 
outlook is overshadowed by the traditional morphological bias and, 
by contrast, how a broader point of view would suffuse greater 
vitality, can perhaps best be illustrated by a few concrete examples. 
In the more elementary practical courses, germination has 
