SULPHATES. PHOSPHATES. 159 1 



Sulphates. In 24 hours, 1-5 to 3 g . 



There are two classes (in proportion 10 : 1) 

 (a) Ordinary sulphates of K and Na derived from proteids. 



of food. 

 (6) Ethereal sulphates. The potassium sulphates of phenol, 



indoxyl, skatoxyl, derived from putrefactive processes in 



the alimentary canal. 



Recognition : 



Class A gives a pp with barium chloride. 



B after boiling 



with a mineral acid. 



Phosphates. In 24 hours, 3-5 g P 2 O 5 . 



Three kinds of salts : Basic (or normal), M 3 PO 4 ;, 

 monophosphates (neutral), M 2 HPO 4 ; diphosphates (acid)> 

 MH 2 PO 4 . 



Clinically they are of importance from two aspects : 



1- Reaction of urine. Acidity largely due to NaH 2 PO 4 , and 



alkalinity to Na 3 PO^. 

 2. Solubility. Affects the production of sediments and calculi, 



(a) Soluble phosphates. Na, K, NH 3 do not deposit 1 in prop. 



(b) Insoluble phosphates. Lime and magnesia J 3:1 



The earthy phosphates (6) are pp in an alkaline medium, 

 hence they appear as sediments in alkaline urine. In ammo- 

 niacal urine they form crystalline deposits as follows : 



1. Ammonio magnesian or triple phosphates, (a) Knife rest 



or coffin lid ; (6) feathery, if quickly formed. 



2. Stellar calcium phosphates and amorphous deposit. 



On heating urine a turbidity or deposit of calcium 

 phosphates may form, due to the transformation of the acid 

 into the basic variety. 



