SECT. XII. PHYSIOLOGY. 107 
cet. Absorbents have been found in the 
texture of every organ, except the brain; and 
there is every reason to suppose they exist in it 
also, though they have not hitherto been detected. 
Their tubes are extremely small and numerous, 
which unite and form considerable trunks. This 
distribution of their tubes is favourable for capil- 
lary attraction. 
cet. It is almost universally admitted at 
present, that the motion of the lymph and chyle 
in the absorbents, is the effect of a contractile 
power which they possess: but how a contractile 
power alone can suffice to draw up and move on- 
wards a column of fluid in a tube, is, I confess, 
to me quite incomprehensible. It is easy to con- 
ceive, that when the mouth of an absorbent con- 
tracts upon a fluid, it must be impelled forward 
in its canal; but if the mouth of the absorbent 
remain contracted, nothing can be plainer, than 
that the chyle or lymph will be effectually ex- 
cluded. This position may be elucidated by a 
rather homely example: the lips form the orifice 
of an absorbent upon a large scale; but let a 
person close them firmly, by contracting the orbi- 
cularis oris, and try to draw any fluid into his 
mouth, he will never succeed till the orbicularis 
is relaxed. If the absorbents have only a con- 
tractile power, their mouths would continue in a 
state exactly similar to the lips of a man-trying to 
