272 
BEY. J. T. GULICK ON DIVERGENT EVOLUTION 
the incompatible forms is as truly a cause of divergence as the 
inferior opportunity for crossing which from the first existed 
between the members occupying different localities or between 
the flowers growing on different trees of the same species. The 
former has been called Negative, and the latter Positive, Segre- 
gation, not for tlie sake of distinguishing different grades of 
efficiency, but for the sake of indicating the different methods of 
operation in the two classes of Segregation. 
(c) Institutional Segregation. 
Institutional Segregation is the Reflexive form of Rational 
Segregation. It is produced by the rational purposes of man 
embodied in institutions that prevent free intergeueration be- 
tween the different parts of the same race. 
As the principal object of the present paper is to call attention 
to the causes of Segregation acting independently of effort and 
contrivance directed by man to that end, it will be sufficient 
to enumerate some of the more prominent forms under which. 
Institutional Segregation presents itself, noting that some of 
these influences come in as supplemental to the laws of segrega- 
tion already discussed, simply reinforcing by artificial barriers 
the segregations that have their original basis in nature. The 
chief forms that should be enumerated are National, Linguistic, 
Caste, Penal, Sanitary, and Educational Segregation ; and if we 
had not already considered Industrial Segregation in the previous 
chapter, tliat might be added. 
Concluding Remarks. 
Besides Artificial and Institutional Segregation, which depend 
on the rational purpose of man, we have now considered numerous 
forms of Segregation, resting on no less than 18 groups of purely 
natural causes. Owing to the length of this paper I deem it 
wise to bi’ing it to a close without discussing the laws that co- 
operate in intensifying the effects directly produced by the 
segregative causes already considered. As I have shown in 
Chapter II., Segregation is not simply the Independent Genera- 
tion of the different sections of a species, but the Independent 
Generation of sections that differ ; and though no one will 
believe that any two sections of a species are ever exactly equi- 
valent, it is evident that the degrees of difference may be greater 
