SECT. IV. PHYSIOLOGY. 25 
lymphatics. The pores of the skin are extremely 
numerous, Leewenhoeck reckoned 12,000 in a 
square inch; they are largest on the nose and 
back, where they are quite visible to the eye. 
xxxvi. The whole of the dermoid system 
expands and contracts; but in some parts the 
irritability is greater than in others. This ex- 
ception being made, wherever the animal heat is 
greatest, there also the expansion of the skin is 
most considerable. This rule is equally applicable 
whether the augmentation of heat be local, as in 
phlegmon, or general, as in common continued 
fever. — 
xxxvit. Expansion of the skin, and animal 
heat, do not, however, stand in the mutual rela- 
tion of cause and effect; they both result from 
the vital force; but the degree of expansion may 
in general be estimated with tolerable accuracy 
by the degree of animal temperature. 
xxxvi. The part of the skin which possesses 
the greatest irritability, is unquestionably the scro- 
tum: diminish its vitality by the application of 
cold, iand it instantly corrugates itself; restore 
its natural degree of vital force by an increase of 
temperature, and how speedily it again expands! 
xxxix. While the animal heat ranges between 
97° and 101°, the skin permits the free egress of 
the sweat through the extremities of the exha- 
lants ; but when it rises above this, the expansion 
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