SUBSTANCES CONSUMED IN THE OEGANISM. 437 



lates etc. With respect to their uses, it can only be said that with calcium phos- 

 phate they go to form the organized structures of which they are necessary 

 constituents. They are discharged from the body in the urine and faeces. 



Sodium Sulphate, Potassium Sulphate and Calcium Sulphate. Sodium 

 sulphate and potassium sulphate are identical in their situations and appar- 

 ently in their uses. They are found in all the fluids and solids of the body 

 except in the milk, bile and gastric juice. Their origin in the body is from 

 the food, in which they are contained in small quantity, and they are dis- 

 charged in the urine. Their chief office appears to be in the blood, where 

 they tend to preserve the fluidity of the albuminoid matters and the form 

 and consistence of the blood-corpuscles. Calcium sulphate is found in the 

 blood and faeces. It is introduced into the body in solution in the water 

 which is used as drink, and it is discharged in the faeces. Its office is not 

 understood and is probably not very important. 



Ammonium Chloride. This substance has simply been indicated by 

 chemists as existing in the gastric juice of ruminants, the saliva, tears and 

 urine. It is discharged in the urine, in which it exists in the proportion of 

 0*41 part per 1,000 (Simon). Its origin and uses are unknown. Various 

 combinations of bases with organic acids taken as food, as l^he acetates, tar- 

 trates etc., found in fruits, undergo decomposition in the body and are trans- 

 formed into carbonates. In this form they behave precisely like the other 

 inorganic salts. 



SUBSTANCES CONSUMED IN THE ORGANISM. 



All of the assimilable organic matters taken as food are consumed in the 

 organism, and none are ever discharged from the body in health in the form 

 in which they entered. The matters thus consumed in nutrition have been 

 divided into nitrogenized and non-nitrogenized ; and although they both dis- 

 appear in the organism, they possess certain marked differences in their prop- 

 erties and probably, also, in their relations to nutrition. 



Nitrogenized Constituents of the Body. The organic nitrogenized con- 

 stituents of the body are composed of carbon, hydrogen, oxygen, nitrogen 

 and sulphur. The exact proportions of these elements are not definitely 

 fixed, and the nitrogenized matters may change in their general characters 

 without undergoing corresponding changes in their actual ultimate constitu- 

 tion, unless it be in the arrangement of their atoms. They are coagulable 

 and non-crystallizable. They possess certain properties in common with 

 each other, which have already been described more or less fully in connec- 

 tion with the physiological history of the blood, alimentation, the secreted 

 fluids etc. One of these properties is a tendency to decomposition by putre- 

 faction, under certain conditions of heat and moisture. They also undergo 

 certain changes under chemical manipulation, analogous to those already 

 described as effected by the prolonged action of the pancreatic juice. The 

 type of substances of this class is the albumin of white of egg, and as a 

 class, they are generally known as albuminoids. Artificial subdivisions of 

 these substances have been made into proteids and albuminoids, the latter 



