116 ANALYTIC SECT. XIV. 
medulla oblongata, But I am here only to regard 
phrenology in so far as it is connected with the 
irritability of the brain. 
ccLxxvi. The white substance of the brain is 
distinctly of a fibrous texture, which may be 
traced from the medulla oblongata into all ‘the 
convolutions; and according to this manner of 
dissecting the medulla oblongata, is the origin of 
the brain and cerebellum, and forms a common 
centre of communication in the nervous system. 
Acephalous monsters, and comparative anatomy, 
evince that vitality may proceed without any 
assistance of the brain, whose office in the human 
species is more of an intellectual than of a vate 
description. 
ccLxxvil. The operation of the Sirnit: in the 
production of ideas, will, in all probability, for 
ever defy our researches; as it is impossible to 
carry expeyiments into the delicate structure of 
this organ, even in the lower animals, without 
previously destroying its natural connexions; in- 
duction is therefore the only means by which any 
knowledge of the irritability of the brain can be 
obtained, As its white substance is fibrous, it is 
reasonable to suppose it is possessed of mobility 
When the fibres of any other organ are kept long 
in one position, an uneasiness is produced, and a 
desire to change their state; the same thing oceurs 
in the brain: when the attention is long directed 



