OF THE FLUIDS. 83 



principle which the blood distributes to all the organs, it is also 

 the vehicle of the warming principle. 



79. The blood varies steadily according to the age, sex, 

 and other circumstances; it also offers accidental changes. 



In the foetus, the blood, which is very dark, has scarcely 

 any coagulable matter. It is the same with the menstrual 

 blood of women. Arterial has a greater proportion of coloured 

 particles than veinous blood. In those individuals that use 

 succulent food, the blood abounds with clot; it is more serous 

 under opposite circumstances. The repeated abstraction of 

 blood, diminishes the proportion of the coloured particles, and 

 even the albumen, but it augments that of the water. 



In disease, the blood suffers changes that have not been suf- 

 ficiently studied. In inflammations, the clot of the extracted 

 blood becomes covered with a white coat, this is the fibrine: 

 and in the clot is also to be seen a large quantity of free colour- 

 ing matter. In particular cases, such as the scurvy, and in 

 septic disorders, the blood loses its coagulability, it remains 

 fluid. There are many diseases on which an attentive exami- 

 nation of the blood would throw great light. 



80. The liquids poured into the blood are the chyle and 

 the lymph. The first comes from the chyme, a grayish, pul- 

 taceous substance, into which the aliments are changed in the 

 stomach, and in which little globules begin to appear. Ab- 

 sorbed by the parietes of the intestine, and having arrived in 

 the first chiliferous vessels, it is whitish and hardly coagula- 

 ble, it becomes more so, and assumes a rosy tint in the glands 

 of the mesentery. Finally, when in the thoracic duct, and 

 ready to pass into the blood, it is distinctly of a rose colour, 

 evidently coagulable, and contains naked globules and parti- 

 cles, which differ from those in the blood, only by an inferior 

 strength of colour. It seems thenceforward to need nothing 

 but the respiratory process to become perfect blood. The 

 lymph, a colourless, viscid, albuminous liquid, but little un- 

 derstood, is the remaining fluid carried to the blood. 



81. The humours which emanate from the blood, are se- 

 parated from it by secretion. We may consider the nutritive 

 matter left by the blood in all the organs, as being of this class; 



