48 feEL-RfrroRV organs— fhe liver. 



sorption (like the lymphatics); tne largest whereof lying along the mesentery 

 (as I said before), sends out smaller branches, and these again more minute 

 ones, to encircle and penetrate the gut; in this their mouths do incessantly 

 suck up, or absorb, and convey to the larger vessels the material for replenish- 

 ing the system with new blood. Passing along the spine, the large tube, filled 

 wilh this milky fluid, at length reaches the fore part of the annual, and ac- 

 quires the name of the thoracic duct ; here it mixes with a portion of lymph, 

 and is conveyed immediately by a large vein to the heart. Ascending the 

 pulmonary artery, as described in a former section (37), the air entering the 

 lungs, changes its colour to a fine healthy scarlet, and at the next pulsation it 

 is driven into the circulation to mingle with the mass, to impart its newly ac- 

 quired properties, and to return again and again, wasting away, until at 

 length it becomes used up and extinct, its place being supplied with other new 

 matter by the continued process of digestion. A change of substance this, 

 which is said to take place with the whole body of the horse in the course of 

 every year and a half, or two years : so that at no time has he a particle of flesh, 

 bone, hair, hoof, or other matter which formed his body two years before, and 

 alfording a fit subject for reflection and admiration in us, as it invites those 

 who have the care of providing for his health to take advantage of the well 

 known circumstance, the more securely to effect those changes by gradual 

 means, which too frequently are attempted by violence, and fail. Nature will 

 not be forced, rather seek her in her recesses, and humour her ways. Those 

 who act differently, generally induce some lasting disorder to appear upon the 

 Burf;>ce, which tliey treat as if local; when, alas! these are seated in the ve-^ 

 vitals of the animal, sometimes in the most delicate parts of the mesentery. 

 Heating, or cordial medicines, as well as those other untoward mixtures, 

 which corrode, or blunt, the mouths of the finer lacteals, thereby dispose them 

 to receive materials improper for the making of good blood; the consequence 

 whereof is, that tubercles frequently are found, which fill up the cavities of the 

 lacteal duct. The matter of these tubercles is usually hardened, and resem- 

 bles the yolk of a hard boiled egg. The disease appears in a staring coat, is 

 commonly considered to be the worms, and treated as such, with more heating 

 or drastic medicines, winch but increase the evil. Other obstructions are 

 thereby formed, and if a solitary worm or two are found on dissection (as fre- 

 quently happens), they have been generated in the obstructed part, but have 

 not caused any disorder. 



Of the mesenteric canal, it may be useful, as well as curious, to remark, 

 that 1 have always found its state of health or disease to correspond with the 

 appearance of his coat ; when this is smooth, the former is full and free from 

 obstructions; when rough, the contrary. In hide-bound, thiscanal is yellow; 

 in farcy, red, as well as the bowels; these appear bluish, when the horse dies 

 in consequence of being worn out, though at the same time, the flaccid lac- 

 teals still preserve their healthy white, if no other cause to the contrary pre- 

 vails. But, upon such further particulars as are connected with the study of 

 digestion, as influencing or influenced by res|)iration and circulation, I shall 

 take occasion to say more hereafter; adding thereto a few cursory remarks, 

 that were not absolutely necessary for the present illustration of the animal 

 system, but will be found more in place in the succeeding section. 



The Liver with its sweetbread, the Kidneys, and the Bladder, being liable 

 to certain diseases peculiar to each, besides the property of affecting one ano- 

 ther readily, as well as being at all times mainly instrumental in maintaining 

 anu restoring health to the other parts of the whole system, now claim our 

 undivided attention. I shall, therefore, proceed at once to a brief description 

 •;if the uses and functions of each, and accompany the same with a fow gene 



