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MANUAL OF MODERN FARRIERY. 
some astringent mixed with the water, such as a small 
portion of vinegar. 
The skin of the heel has numerous glandular pores, 
through which the unctuous secretion oozes; and sometimes 
these are unduly excited, and this matter becomes altered 
in its substance and odour, and produces that disease called 
grease, described at page 144, and which in some instances 
proves somewhat difficult to cure. 
The cutis, when destroyed by any means, does not 
regenerate quickly. Great care should therefore be taken 
not to allow any portion of it to be broken. Many think 
that it is of little consequence for horses to have the skin 
of their back rubbed off by friction from a saddle. Such 
parts as have lost their cutis have it but slowly reproduced ; 
and even when it has been restored, its vital power k 
much weaker than it originally was ; for, although it ap¬ 
pears at first to be very vascular, its vessels after a time 
either shrink in calibre, or some of them become altogether 
obliterated It invariably happens that when horses have 
had fistulae or saddle-galls, they are always more disposed 
to subsequent injury in those parts. 
THE RETE MUCOSUM. 
The third part of the skin consists of a membrane which 
bears this name; it is a fine, delicate, laminated tissue, 
interposed between the cutis and the cuticle. The skin 
takes its colour from this membrane. It is from this mem¬ 
brane being black in the negro that he takes his dark 
colour ; for dissection has proved that his cuticle when 
separated from this membrane is as white as that of a 
European. Its use appears to afford protection to the 
delicate vessels of the nerves from outward injuries. 
