29 



if he sweats, does not porspire above six. This he tried 

 many times, and never found it to fail. Whence he 

 infers, 1. That it is not the same matter which is 

 evacuated by insensible perspiration and by sweat ; 



2. That it is not evacuated through the same pores : 



3. That the sweat.pores are abundantly larger and 

 fewer, than those which serve insensible perspiration : 



4. That sweat greatly hinders that perspiration, both, 

 by covering those pores with a clammy liquor, and by 

 constringing them so that they cannot open, which 

 must be the ease, when the sweat pores are dilated. 

 What a field does this open ! 



Some queries proposed concerning perspiration, by 

 an ingenious writer, seem to deserve a serious conside- 

 ration. 1. " Why do carnivorous animals sweat 

 50 little? A fox hunted almost to death never sweats. 

 2. Why do those which feed on vegetables perspire 

 so much? Horses and cows for example. We may 

 often see them involved in a cloud of their own va- 

 pours, yea, almost covered with froth. 3. How can 

 animals, whose natural food is vegetables, be kept 

 alive, and in health, in very cold climates, by purely 

 aninral food ? Cows in Iceland and Norway are fed 

 in winter upon fish-bones." I would beg leave to ask 

 4. Do the sweat pores only imbibe? Or those also s 

 which serve for insensible perspiration f 



15. Fat, a whitish oily substance, void of sense, is 

 secreted from tha blood, and lodged in small oval, 

 membranous bags, which shoot out of the arteries. It 

 is found in various parts, but chiefly under the skin, 

 where (unless a man be emaciated) it runs co-extended 

 with the skin over most parts of the body. 



Fat is secerned from the arterial blood by the adi- 

 pose glands, and transmitted again from the membra- 

 nous cells to the blood through the veins. It seems 

 to be a portion of the blood coagulated by the nitrous 

 air mixed with it in the lungs. Artificial fat is made, 

 by mixing for some dap oil of olives with spirit of 



