114 



A thousand ounces of blood pass through the renal tissue in the space 

 of an hour : supposing that this fluid contains only a tenth of the materi- 

 als fit for supplying urine, a hundred ounces, or seven pounds and a quar- 

 ter, may be given out in this short time; and never, with the most co- 

 pious and diuretic drinks, does more of it pass in an hour. We shall 

 see, however, in treating of absorption, that it is not absolutely impossi- 

 ble, that by means of the numerous anastomoses of the lymphatics, this 

 set of vessels may carry a liquid, directly from the stomach into the blad- 

 der. It would be superfluous to mention, in this place, the varieties ob- 

 servable in the kidneys, in point of number, size, and situation. These 

 two lobular viscera,xomposed of the union from twelve to fifteen glan- 

 dular bodies, divided in the foetus, and in some quadrupeds, attached to 

 the posterior part of the abdomen, behind the peritoneum, are surround- 

 ed with a cellular covering of different thickness, and particularly remark- 

 able by the consistence, approaching to that of tallow, of the fat which 

 fills its cells. 



If ever the art of man shall penetrate into the mystery of the intimate 

 structure of our organs, it seems probable that the kidneys will furnish 

 the first solution of the problem*. Even coarse injections pass readily 



the prussiate is injected, it can be detected in the blood by means of re-agents ; but 

 when the quantity is small, it is impossible to discover its presence by any of the usual 

 tests. 3. That the same thing takes place if the prussiate be mixed with blood in a 

 vessel. 4. That this salt may be detected in the urine in any proportion, and therefore 

 it is by no means extraordinary, that DARWIW and BRAJTIJE could not find in the blood 

 a substance which they easily perceived in the urine. Mag. Phys. Vol. II. p. 380. 



The existence of absorbent vessels which open into veins along their smaller ramifi- 

 cations, and even towards their terminations, and the frequent anastomoses of the form- 

 er set of vessels with the latter, all which appears to be satisfactorily shown, (See AP- 

 PENDIX, Note Q.) sufficiently explain the rapid transit of liquids, or other substances, 

 from the stomach and other parts of the bo6y into the circulating fluid, and their quick, 

 but subsequent, appearance in the secretions, 



In consequence of the activity of those secreting organs whose chief function it is to 

 remove substances from the blood, which would become deleterious from their accu- 

 mulation in it, and owing to the stimulus which such substances give these organs when 

 conveyed to them in the course of the circulation, they are eliminated from the blood 

 as last as they enter it, so that they seldom can be present in sufficient quantity to be 

 detected by the usual chemical agents. Copland. 



* One of the latest and most minute dissections of the kidney, has been made by 

 EYSENHABDT, of Berlin, (De structura renum Observationes Anatomies, Ber. 1818, 

 4to. His observations were made on very thin slices of the kidney cut longitudinally, 

 and also in the short diametet : these were wetted with diluted alcohol, and examined 

 in the microscope. The experiments were originally made to discover the peculi- 

 arity, it any, of a diabetic kidnev ; but no perceptible difference was found to exist be- 

 tween the diabetic and healthy sttte of this organ. 



The naked eye discovered sm*i p 0mts O n these slices, which the microscope re- 

 psesented as oval and sometimes rt nn d granulations, situated at different distances 

 from each other, and varying in size, i^th in the same kidney and in the kidneys of 

 different sexes. After maceration, thesx g^ n9 cou i d be detached with their adher- 

 ing vessels, and a void was left. They wy e composed of knotty vessels, surrounded 

 by an ash-grey substance, and united, not j*, muc h by frequent anastomoses, as by 

 numerous meetings with each other. The a^. co loured substance was not granular; 

 it appeared as if traced with * pencil. Injectio, by the renal artery made these cor- 

 puscules wholly red ; but still, some deeper and e\her clearer points could be perceiv- 

 ed in them. Dr. E. considered these corpuscules u be the glandules and glomerules 

 of MALPIGHI and of SCHUMLANSKY. He could not tn c e the veins arising from these 

 glandules ; but he refers to an observation of PIIOCHASCR<, in which a successful injec- 

 tion of the renal vein showed, under the microscope, a \<?.ry loose, vascular little net, 

 surrounding the isolated corpuscules of the cortical substanc< " Dr. Mapes, of Frank- 



