04 On Idiotism. 
two affections so often intimated by travellers, 
and which Fodere has endeavoured to esta- 
blish, must be considered as more than doubt- 
ful and uncertain. 
Considering the connexion of these affec- 
tions in the most simple point of view, as 
two distinct endemics appearing in the same 
Jocal situation, it may still be asked how 
their frequent conjunction in the same indivi- 
dual is to be accounted for? In this circum- 
stance there is nothing new, nor at all con- 
trary to our experience of the co-existence 
of disease ; it only seems to shew an intimate 
connexion betwixt their causes, if it does not 
shew them to be the same, whilst the effect is 
influenced by the habits, tendencies, and pre- 
dispositions of the individual exposed to their 
action; it is this absence of predisposition 
which enables so many to remain in perfeet 
health though exposed during a long life to 
causes, which in other habits produce the 
most injurious consequences. 
It might be thought that physical causes 
producing an influence thus powerful over 
the” developement of the mind and_ the 
body, could be easily ascertained, but this 
is not the case. Many of the ascribed causes 
are inadequate to the effect, or must produce — 
it more generally ; whilst others are at vari- 
