62 MANUAL OF HISTOLOGY. 



nary phosphoric acid occurs in the body, whether as an acid salt with one 

 atom of base and two molecules of water, or a neutral as it is called, in 

 which two atoms of base go to one molecule of water. The salt is met 

 with in the juice of muscle (Liebig). 



SULPHATE OF POTASSIUM, K 2 S0 4 . 



Appears in the body, probably, with the corresponding salt of sodium 

 and under similar circumstances. 



Ammonium Salts. 



The physiological processes of the body are attended by but a compara- 

 tively small development of ammonia, so that in this respect they may be 

 said to offer a contrast to putrefactive decomposition. The combinations 

 of ammonium in the body are probably of various kinds ] for the present, 

 however, we are unable to enter into them very fully. 



CHLORIDE OF AMMONIUM, KH 4 C1 . 



It is still an undecided question how far this or the carbonate appear 

 in the economy. 



CARBONATE OF AMMONIUM. 



Is found in expired air, in decomposed urine, in blood, in the lymphatic 

 glands and blood-vascular glands. The combinations which are here met 



2CO ) 

 with are the sesquicarbonate /-M-TT \ TT > 04, and bicarbonate NH 4 .HC0 3 . 



Iron, Fe, and its Salts. 



This metal is extensively distributed throughout the body, and occurs 

 probably in all its parts. It is met with in various forms also, being sup- 

 plied to the system in great abundance with the food. 



In some way not very fully understood at present, iron enters into the 

 composition of the most important of all animal colouring matters, haemo- 

 globin (p. 18). Uroerythrin and melanin also contain iron (p. 52). 



PROTOCHLORIDE OF IRON, FeCl 2 . 



This salt is said by Braconnot to be present in the gastric juice of 

 dogs. 



PHOSPHATE OF IRON, Fe 2 P 2 8 . 



Another compound of iron generally accepted, though perhaps on in- 

 sufficient grounds, as occurring in the living body. 



In regard to the presence of iron one thing is certain, namely, that all 

 portions of the body supplied with blood must contain it. It has also 

 been found in chyle, lymph, urine, sweat, bile, and milk, and finally in 

 hair, cartilage, and other solid tissues. 



Manganese, Mn. 



This metal is introduced into the system in company with iron, and is 

 met with here in minute quantity. It seems to be merely an accidental 

 constituent. It is found in hair, and in biliary and urinary calculi. 



Copper, Cu. 



Copper has been noticed in the blood, bile, and biliary calculi of man. 

 It is excreted by the liver. 



