SECT. XIII. PHYSIOLOGY. 113 
SECTION XIII. 
Visceral Irritability. 
ccLxx1. Although the functions of the different 
viscera are extremely dissimilar, yet there is a con- 
venience in studying their irritability in the order 
of anatomical demonstration. Under this genus 
of irritability, I shall therefore include the motions 
of the brain, the iris, the lungs, the alimentary 
canal, the bladder, uterus, and penis. These 
organs so far resemble each other, that they are 
all composed of a fibrous texture that possesses 
irritability, though in very different proportions 
in its respective organs. 
ccLxxu. The heart has been excluded from this 
genus, as forming part of the vascular system, of 
whose functions it would have been impossible to 
treat with any degree of consistency separate 
from the primum mobile of the circulation. The 
irritability of the glands might also have been 
accurately brought under visceral irritability ; but 
as their structure is not fibrous, and to treat 
of their functions would swell my work to an 
unnecessary size, they are left out. 
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