52 THE PRINCIPLE OF URINE. 



M The section of a kidney, which should be performed lengthwise, wiR 

 show in the centre its pelvis, in which the tube (or ureter) that carries off the 

 water to the bladder takes its rise : in this pelvis stone is sometimes formed, 

 that often finds its way to the bladder, unless it remains in the ureter, or comes 

 away entirely.* The ureters communicate immediately with the bladder, and 

 the water they convey is formed by the outermost red part of the organ draw 

 ing the blood into it, and through which it is filtsred by the vascular or whitish 

 part which lies next withinside ; here numerous little tubes convey it to the 

 centre one, or ureter, that enters the cavity of the pelvis at H I, 33, 34, of the 

 plate of a skeleton. 



The blood, which has been so filtered of its water, is absorbed by a vein, 

 which is plainly visible in the section of the kidney ; and the whole function 

 shows how rapidly circuitous any medicine must act, which being poured into 

 the stomach is found, in so short a space as two or three hours, to have work- 

 ed its passage through the bowels into the lacteals, thence through the heart 

 and arteries into the kidneys, filled the bladder, and caused a staling of the 

 noxious water, which is to carry off disorders of one sort or other. Here it is 

 worthy of remark, that the operation of internal medicines is much more cer- 

 tain in the horse, when directed against the absorbing vessels and the kidneys, 

 than when intended to act chiefly on the stomach ; for, as hath been observed, 

 nis stomach being one half of it insensible to stimulants, we are not certain of 

 producing upon it any effect whatever. In all swellings of the legs, the good 

 properties of diuretic medicines may be discerned almost immediately, by reason 

 of the connexion which subsists between the functions of lymphatics and of 

 the kidneys ; so likewise, diaphoreiic medicines no sooner excite the lacteals 

 to a performance of their function, than the skin shows evident signs of its 

 good effects. But both means of cure msiy be abused, as 1 shall show more 

 particularly in the sequel : the first, being administered too often, wears out 

 the functions of the kidneys; the second, being carried on too long, at length 

 refuseth to act upon the skin. 



55. An idea respecting the deposition of water in the membranes was 

 thrown out in the twentieth section ; and another, as to variation in the pro- 

 portions of urine and perspiration in summer and winter, at the bottom of 

 section the twenty-second, to which the reader may refer. On this topic a 

 foolish notion having got abroad as to the small quantity of acrid matter con- 

 tained in the urine of the horse, induced Dr. Thomsont to submit a portion 



• I was called in to examine a horse, whose diseases had baffled the skill of many clever 

 farriers. He had been long declared to have " a complication ; " that is to say, none icnew his 

 disease, lor he occasionally voided blood with his urine, in great pain ; they had thei-efore given 

 him diuretics to such an excess, that he could not bear the h;ind's passing along his back over 

 the kidneys: his sheath showed signs of oedematous swelling, and upon that region being 

 pressed he became unruly. I, however, saw enough to ascertain, by the heat and tension of 

 the pcul, that it was inflammatory, and as his pulse was high, his tongue hot and dry, I pro- 

 posed to bleed him, and to foment the part ; the operation, however, was scarcely performed 

 when its owner resolved to take no further trouble, and the horse was slain. On examination 

 I found his kidneys were rotten, and as pervious as dough : ulcers appeared upon both lobes of 

 the liver, and the neck of the bladder was inflamed a little. The sheath presi.Tved its size ; and 

 on the top of the penis a small shapeless stone, the cause of all this mischief, lay buried under 

 the cuticle; and would, I should apprehend, have come away in the course of a day or two 

 fpcn'.aneously. How it got there is most inscrutable. 



t or Edinburgh, in his Annals of Philosophy, for August, 1820. By the way, on this sub- 

 ject it is worthy of remark, that for seven or eight years past, the French and Italian doctora 

 Oave made a gi-eat fuss about this I'uree (nrea),"or proportion of the principle of urine, calling 

 'R "a discovery ; '" whereas our own people, in every branch of medicine, have been aciing up> 

 un the same doctrine for better than forty yearS; to my certain knowledge. Some have regu- 

 'ated their practice (human) by the appe^irance of the water, with various success; and I have 

 ^ great notion, that this test of the state of the horse's health may be added la those other g^-mp 

 wmsby which we endeavour to ascertain the ailments of an animal which aatureliasforbiddeo 



