71 



sense. Some beiiere it depends on the suitableness of 

 the fluid secerned, to the shape of the secerning 

 pores. Some lay the stress rather on the various 

 size and diameters of those pores : others on this, that 

 the constituent particles, suppose of the bile, froni 

 their peculiar proportion, texture, and figure, may be 

 more easily united to each other, than to the particles 

 of lymph, or any other (hud. 



52. The chief of all the fluids in our body, and the 

 fountain of life, is the Blood. It consists of a watry 

 serum, fibrous particles, and red globules, which 

 last are scarce a twelfth part of it. It is generated 

 thus. The meat and drink being digested into chyle, 

 pass from the intestines, through the lacteal veins and 

 the thoracic duct, into the left subclavian. vein, and 

 thence into the vena cava, where it mixes with the 

 blood ? and then circulates with it, till it is wholly 

 assimilated. 



Blood, fresh drawn, appears to the naked eye, uni- 

 form and homogenous. But when cold, it separates 

 into two parts ; the one red and fibrous which clots 

 together ; the other thin and transparent, called the 

 serum, in which the former swims. The serum is in 

 bulk three fourths of the blood; in weight fifteen 

 seventeenths. 



A red globule is computed to be 25,000 times 

 smaller than the smallest grain of sand. 



But whence arises the heat of the blood ? This 

 deserves a particular enquiry. 



Fermentation is that spontaneous, intestine mo. 

 tion, which by the heat of subterraneous caverns, will 

 in a few hours so change vegetable juices, (for fer- 

 mentation is confined to the vegetable kingdom) as 

 from a vapid wort quenching fire, to nourish fire, 

 and to afford that inflammable liquor, commonly cal- 

 led spirits. 



Effervescence arises from an intestine motion ex- 

 cited in various fluids, by the mixture of other fluids, 

 or of salts or powders of a different nature. Acids 



