88 LABORATORY WORK IN PHYSIOLOGICAL CHEMISTRY. 



Read off on the graduation of the spindle the mark where 

 the meniscus of the fluid cuts it. 



Sediments. Notice should be taken as to their color, 

 amount, character, etc. The method for the determination 

 of the identity of such will be taken up later. 



Total Solids. These may be calculated approximately by 

 multiplying the second and third decimals of the specific 

 gravity by Haser's coefficient = 2. 33. This gives the number 

 of grammes in 1000 c.c. of the urine, from which must be 

 calculated the total amount in the twenty-four hours. 



THE NORMAL CONSTITUENTS OF THE URINE. 

 INORGANIC COMPOUNDS. 



Concerning the exact nature of the combinations formed 

 in the urine by the various bases and acids (ions) but little 

 is known at present. The compounds are present in rather 

 dilute solution and as such are amenable to all the chemical 

 and physical laws of salts in like solutions, complicated, 

 however, by the fact that the condition is not one of a single 

 salt in a simple solution but of an exceedingly complex mix- 

 ture of salts both inorganic and organic. The dissociation 

 of one salt is influenced by the presence of others, also disso- 

 ciated, and the particular combinations of the various (ions) 

 bases or acids depend upon their relative masses and avidities. 

 Again, as regards two compounds with like ions each de- 

 creases the solubility of the other, while the solubility of 

 unlike ions is increased by their mutual presence. 



These factors, dissociation, mass action, and affinity deter- 

 mine the character of the ionic equilibrium which is present 

 in the urine, but as to the exact nature of such equilibrium, 

 our present methods tell next to nothing. The later work 



