628 THE AMERICAN NATURALIST. [Vow. XXXII. 
evolutionary idea will be taught in our primary and secondary 
schools. 
The rapidity with which evolutionary conceptions have taken 
root and spread may be compared to the rankness of growth of 
a prepotent plant or animal on being introduced into a new 
territory where it is free from competition. It has indeed 
swept everything before it, occupying a field of thought which 
hitherto had been unworked by human intelligence. 
The immediate effect, and a very happy one, of the accept- 
ance of the theory of descent on working zodlogists is to 
broaden their minds. Collectors of insects and shells or of 
birds and mammals, instead of being content simply to acquire 
specimens for their cabinets, are led to look during their field 
excursions for examples of protective mimicry, or to notice 
facts bearing on the immediate cause of variation. Instead of 
a single pair of specimens, it is now realized that hundreds and 
even thousands collected from stations and habitats wide apart 
are none too many for the study of variation as now pursued. 
The race of “species grinders ” is diminishing, and the study 
of geographical distribution, based as it is on past geographical 
changes and extinctions, is now discussed in a far more philo- 
sophical way than in the past. The most special results of 
work in cytology and morphology are now affording material 
for broad work in phylogeny and heredity. 
On the other hand, it must be confessed that, as the result 
of the acceptance of evolutionary views, our literature is at 
times flooded with more or less unsound hypotheses, some 
tedious verbiage and long-winded, aérial discussions, based 
rather on assumptions than on facts. But on the whole, per- 
haps, this is a healthy sign. Too free, exuberant growths will 
be in the long run lopped off by criticism. ; 
One tendency should be avoided by younger students, that 
of too early specialization, and of empirical work without a 
broad survey of the whole field. In some cases our histologists 
and morphologists rise little above the intellectual level of 
species describers. Expert in the use of the microtome and of 
reagents, they appear to have but little more general scientific 
or literary culture than high-class mechanics. The chief anti- 
