URINE. 



1273 



sent state of our knowledge may permit us to 

 see in too attractive a form. 



Liebig remarks, "When the hydrochloric 

 acid (in the stomach) has exercised its solvent 

 action upon the aliments, and the latter have 

 passed into a state of solution, the soda 

 which originally entered the organism in com- 

 bination with the hydrochloric acid, that is, as 

 common salt, rejoins the hydrochloric acid 

 during the preparation of the chyme, and pre- 

 vious to its transformation into chyle, the 

 soda and the hydrochloric acid thus reunited 

 combine again and form common salt : chyle 

 and lymph have no longer any acid reaction, 

 but, on the contrary, they manifest alkaline 

 properties."* The alkaline reaction of the 

 lymph, chyle, and blood of man and of the car- 

 nivorous animals cannot be owing to the pre- 

 sence of a free alkali, as is evident from the 

 preceding observations ; for the nutriments 

 of man and of the carnivorous, as well as the 

 graminivorous, animals, contain no free alkali, 

 nor any salt formed of an alkaline base and 

 an acid which might be destroyed in the 

 organism by the vital process, and thus cause 

 the alkaline base to be liberated. The blood 

 must contain the same salts as exist in the 

 aliments. With the exception of common 

 salt, nothing is added during the digestion of 

 the aliments. We have seen that this substance 

 undergoes decomposition in the upper part 

 of the digestive apparatus, being resolved 

 into free soda and free hydrochloric acid ; but 

 we have also seen that the liberated soda 

 rejoins the hydrochloric acid during the pre- 

 paration of the chyme, and previous to the 

 transformation of the latter into chyle ; that 

 is, when the acid has performed its function, 

 viz. the solution of the aliments, the salt 

 formed by this combination, that is, common 

 salt, has neither an acid nor an alkaline re- 

 action. The salts with alkaline reaction con- 

 tained in meat, flour, or grain, are alkaline 

 phosphates. It is obvious that the alkaline 

 reaction of the chyle, lymph, and blood of 

 animals feeding upon animal and vegetable 

 substances can only be derived from their 

 alkaline phosphates. The serum of the blood 

 can only be considered as a combination of 

 albumen with an alkaline phosphate ; the fibrin 

 of the blood, or the fibrin of the muscular 

 fibre, is a combination of albumen with phos- 

 phate of lime. 



" The bibasic phosphates of soda and of 

 potash are in many respects highly remarkable 

 salts. Although of a tolerably strong alkaline 

 reaction, yet they exercise no destructive 

 action upon the skin, nor upon organic forma- 

 tions. They possess all the properties of the 

 free alkalies, without being such : thus, for 

 instance, they absorb a large amount of car- 

 bonic acid, and this in such a manner that 

 acids produce effervescence in a saturated so- 

 lution of this kind, just as they would in 

 alkaline carbonates. They dissolve coagulated 

 curd of milk or cheese, as well as coagulated 

 albumen, into clear fluids with the greatest 



* Lancet, 1844. 



facility, just as caustic or carbonated alkalies 

 do. But of still greater importance in relation 

 to the secretion of urine is their deportment 

 towards hippuric acid and uric acid. Hippuric 

 acid dissolves with the greatest facility in 

 water to which common phosphate of soda 

 has been added. Uric acid possesses the same 

 property at a high temperature; the phosphate 

 of soda, in this process, loses its alkaline re- 

 action completely upon the addition of uric 

 acid and hippuric acid, and assumes an acid 

 reaction. The acid nature of the urine of 

 man, and of the carnivorous and graminivorous 

 animals, is thus explained in a very simple 

 manner. 



" There are but two principal channels 

 through which the salts entering the organism 

 with the aliments can effect their exit from 

 the body, viz. they must either be carried off 

 in the faeces, or in the urine. The most simple 

 experiments show that soluble salts are car- 

 ried off by the faeces only when the amount 

 of salt contained in the fluids in the intestines 

 is larger than that contained in the blood. 

 If the amount of salt in these fluids is equal 

 or inferior to that of the blood, the soluble 

 salts are re-absorbed by the absorbing vessels 

 of the intestinal tube, and enter the circula- 

 tion, ami are then removed from the body 

 by the urinary organs and channels. If the 

 amount of salt contained in the intestinal 

 tube is larger than that contained in the 

 blood, the salts exercise a purgative action. 



" If, after previous evacuation of the rec- 

 tum, a weak solution of common salt (one 

 part of salt to sixty parts of water) be taken 

 by means of a clyster, no second evacuation 

 will take place : the fluid is absorbed, and all 

 the salt is found in the urine. This experiment 

 yields the most convincing results if ferro- 

 cyanide of potassium is substituted for com- 

 mon salt. In this case the first urine excreted 

 after the injection of the saline solution, and 

 frequently even after so short a time as fifteen 

 minutes, contains so copious an amount of 

 ferrocyanide of potassium as to yield, upon 

 the addition of persalts of iron, a copious pre- 

 cipitate of Prussian blue. 



" The influence which salts in general ex- 

 ercise upon the secretion of urine is in the 

 highest degree worthy of attention. It is a 

 well known fact, that a very speedy emission 

 of urine takes place in healthy individuals 

 after drinking fresh pump-water. If ten 

 glasses of water of from six to eight ounces 

 each, containing no more than ^i^th of its 

 amount in salts, be drunk at short intervals, 

 an emission of urine of the usual colour will, 

 after the lapse of about ten minutes, follow 

 the second glass, and from eight to nine eva- 

 cuations of urine will generally occur in the 

 course of an hour and a half. The urine in 

 this experiment emitted in the last evacuation 

 will be clear and colourless like pump-water, 

 and the amount of salts it contains is little 

 more than is contained in pump-water. There 

 are individuals who are capable of thus im- 

 bibing from six to eight quarts of water con- 

 secutively without any inconvenience ! ! 



