148 
TENTH REPORT. 
the observation of non-significant characters to non-significant characters 
is unnecessary waste of energy. They will never become significant. 
I have stated now what a type is, and the principles that shall govern 
both our selection of the type, and our selection of the characters that are 
to be observed in the study of each. My second proposition is that different 
things selected as types should be related to each other in such a way that 
the comprehension of the relations is not too difficult for the learner. 
The types must not be too widely separated from each other. The 
related forms must be studied. If this is not done there is little value in 
the study of a type. All thinking consists in the perception of rela- 
tions between things. So numerous and so diverse are the relations ex- 
isting in the universe, that we may say that education consists in the 
training of the mind to perceive relations. Any mind can see some of the 
most evident relations, but the mind of the greatest philosopher is incapable 
of recognizing some of those that exist. In order to train the mind to per- * 
ceive relations, it must be set to perceiving them, and the difficulties must 
be graded according to the capacity of the mind to be taught. It is in the 
proper gradation of difficulties that teachers are likely to make mistakes. 
Especially is this true in the teaching of science whose pedagogics is so in- 
sufficiently worked out. We have no adequate statement that I have been 
able to find of the psychology of laboratory science, and no serious attempt 
has been made to frame a course of study in science in terms of the psycho- 
logical movement of the learner. Our books of method in science are books 
of devices, or method in the most limited sense. 
1 would not have it understood that we study only the dead forms instead 
of the living beings, as is sometimes charged against this kind of work. The 
living activities are just as much a character of the type as the morphological 
structures. But the dead body of a beetle is a living thing in the sense that 
every part has been produced by the life of the animal and had some part 
in the life that the animal lived. We study the legs because the animal 
moves with them; the wings because it flies with them; the mouth parts 
because it bites with them. And so it is with every part; each part has 
some meaning in the life of the animal and it is the object of study to interpret 
that meaning. 
Just here I should like to pause long enough to comment upon the value 
that exists in systematic work in botany and zoology. It is a kind of work 
that has of late fallen very much into disfavor, and very properly too, in 
consequence of the great abuse to which it has been subjected. The 
marks that are used to discriminate genera and species are apparently so 
trivial that they seem ludicrous. I merely wish to suggest that the varia- 
tion in physiological function and life habits are usually much more pro- 
nounced than are the morphological differences that can be quantitatively 
stated and used to discriminate species. Even among individuals of the 
same species such variations in personality exist that we need to study 
many individuals of a species in order to obtain an insight into the psycho- 
logy" of the species. Also I would suggest that all the most delicate 
work of the embryologist, the histologist, the ecologist, everybody who 
contributes to the knowledge we possess of an individual of a particular 
species only helps us to arrive at a better understanding of the relationship 
that exists among the various groups of animals and plants, which is pre- 
cisely the thing that t he systematist attempts to do in a rough and ready way. 
Minute discriminations such as the systematist makes are necessary. Who 
would imagine the minute differences in structure would be correlated with 
