658 TRANSACTIONS OF SECTION K. 
inclines to the view that they may be but states of one protean species. Where 
the capacity for detecting differences is naturally strong, the disposition is 
towards segregation ; where there is a keen eye for affinities, the reverse. The 
facts in both cases are the same ; their influence on minds in which the faculty 
of observation, though equally developed, has a natural bias in a particular 
direction may thus be different. 
This inherent variation in mental quality, of which the observer may 
personally be unaware, and over which he may have incomplete control, is 
not, however, so potent a factor as a difference in mental attitude, usually 
the result of training or tradition. The existence of two distinct attitudes 
on the part of authors towards their ‘ species’ is common knowledge. In the 
absence of more suitable terms we may speak of them as the ‘ parental’ and 
the ‘judicial.’ To the parental worker his species are children, whose appeals, 
even when ad misericordiam, are sympathetically received. To the judicial 
worker his species are claimants, whose pretensions must be dispassionately 
weighed. The former treats the recognition of a species as a privilege, the 
exercise of which reflects honour. The latter views this task as a duty, the 
performance of which involves responsibility. With amply characterised 
forms the mental attitude is inconsequent, but when critical forms are 
reviewed it is all-important. Here the benefit of a doubt is the practical basis 
of final decision. This benefit in the case of the parentally disposed worker 
may lead to the recognition of a slenderly endowed species; in the case of 
the judicially inclined, to the incorporation of an admittedly critical form in 
some already described species, the conception of which may thereby be unduly 
modified. 
These attitudes do not in practice divide descriptive workers into two 
definite classes. Some writers display one attitude at one period, the other 
at another period of their career. Occasionally the two alternate more than 
once in a writer’s history. Cases are known in which one attitude is con- 
sistently adopted towards species of one natural family, the other towards 
species of a different family. 
When want of uniformity in delimitation is due to the varying effect of 
the same facts on different observers there is no room for either praise or 
blame. Capacity for appreciating affinities is complementary to that for 
discrimination. The fact that now one, now the other tendency is more highly 
developed makes for general progress. Workers in whom the two may be 
more evenly balanced can strike a mean between the discordant results of 
colleagues more highly endowed than they are in either direction. But those 
who possess a capacity for compromise do not mistake this for righteousness ; 
they are apt to wish themselves more gifted with the opposing qualities of 
those whose work they assess. 
When cases in which want of uniformity in delimitation due to difference 
in mental attitude on the part of independent workers are considered, we 
again find that praise and blame are inappropriate. If both attitudes have 
defects to be guarded against, both have merits that deserve cultivation. 
The defects are patent’ and rarely overlooked ; the careful systematist, more 
critical of his results than anyone else can be, is alive to the risks which 
attend stereotyped treatment, and on his guard against the excesses to 
which this may lead. It is more often forgotten that both attitudes have 
their uses, and that each should be exhibited at appropriate times. Here, 
however, no middle way is possible; the mean between the two attitudes has 
the qualities of a base alloy. It is the attitude of indifference, fatal to 
scientific progress, and productive of results that are useless in technical 
research. 
The ideal arrangement in monographic study is the collaboration of two 
workers, one highly endowed with the discriminating, the other with the 
aggregating faculty. But for the statement of their joint results both must 
adopt the judicial attitude. On the other hand, in floristic work, in isolated 
