123 



stance drops into the bladder, it becomes the nucleus of a calculus, form- 

 ed by the uric acid becoming concrete on the surface of this body, which 

 is of a colder temperature. Quadrupeds are less frequently affected with 

 urinary calculi, from the absence of the uric acid in their urine, and be- 

 cause carbonate of lime, of which, in those animals, such concretions are 

 formed, is a salt decomposed with effervescence by the weaker acids, and 

 several such acids are found in the urine. 



Phosphorus, which may be considered as the result of a high degree 

 of animalization, enters, in considerable proportions, into human urine. 

 Besides the phosphoric salts which it contains, there is always found a 

 certain quantity of disengaged phosphoric acid, which holds in solution 

 the calcareous phosphate, ami {jives to the urine its manifest acidity, when 

 examined fresh, or shortly after it has been voided. It was from urine, 

 that phosphorus was first obtained by those who originally dUrovered it, 

 and from that fluid, it has long been procured for the purposes of com- 

 merce. But it is seldom obtained from urine, since the discovery of the 

 phosphoric acid in the earth of bones, has rendered the manufacture of 

 phosphorus easier and less expensive. In the urine of frugivorous mam- 

 raiferous animals, phosphoric salts have their place supplied by calcare- 

 ous carbonate. 



Certain substances impregnate the urine with a peculiar odour. It is 

 well known that if one remain a few minutes in a room newly painted 

 with oil of turpentine, the urine, for some time afterwards gives out a 

 smell of violets; asparagus gives to the urine- a very remarkable fetor. 



XXXVIII. Besides the accidental varieties observed in the urine, vari- 

 eties which cannot be determined, since the urine is never uniformly tfce, 

 same in its composition, and does not contain the same ingredients in the 

 same person, at different times of the day, according to the quantity and 

 quality of the food and drink, the exercise which has been taken, the af- 

 fections of the mind which have been experienced, &c.; it constantly 

 varies, according to the time which has elapsed since a meal, the age of 

 the subject, and the diseases under which he may labour. 



Physiologists have for a long while, admitted two and even three dif- 

 ferent kinds of urine, according to the time at which it is voided; they 

 are distinguished by the names of urine of the drink, urine of the chyle, 

 and urine of the blood. The first is a limpid and nearly colourless fluid, 

 which frequently retains, in a remarkable manner, the qualities of the 

 drink, and is voided shortly after drinking, and has scarcely one of the 

 characters of perfect urine. The urine of the chyle or of digestion, 

 voided two or three hours after a meal, is more formed, still it is not per- 

 fect, and does not contain all the component parts of this fluid. 



Lastly, the urine of the blood which is voided seven or eight hours after 

 a meal, and in the morning after the night's- rest, contains, in an eminent 

 degree, all the qualities of urine, hence it is that which chemists prefer 

 using in their analysis. The imperfect state of the two former kinds of 

 urine, would prove better than the rapidity of their secretion, the disputed 

 existence of a peculiar communication from the stomach and intestines 

 into the bladder. 



The urine of children and that of nurses contains very little phosphate 

 of lime and phosphoric acid ; it is only after the process of ossification is 

 completed, that these elements abound in the urine. That of old men, 

 on the other hand, contains a considerable quantity of these substances $ 

 their osseous system already containing phosphate of lime in excess, and 



