CHEMICAL COMPOSITION OF THE BODY. 21 



oxygen; some contain nitrogen also. There are three chief 

 kinds of them, viz. : albumens, fats, and carbohydrates. 



Albuminous or proteid substances. These are by far 

 the most characteristic organic compounds existing in the 

 body; they are only known as obtained from living beings, 

 having never yet been artificially constructed in the labo- 

 ratory; a good example is found in the white of an egg, 

 which consists chiefly of albumen dissolved in water. All 

 the tissues of the body which have any marked physiolog- 

 ical property contain some albuminous substance, only 

 such things as hairs, nails, and teeth being devoid of 

 them. All albuminous bodies contain nitrogen, carbon, 

 hydrogen, and oxygen; most of them sulphur and phos- 

 phorus in addition. The more important ones found in 

 the body are, (1) Serum albumen, which is very like egg 

 albumen, and is found dissolved in the blood; (2) Fibrin, 

 which forms in blood when it clots; (3) Myosin, found in 

 the muscles and "setting" or coagulating after death, when 

 it causes the death stiffening; (4) Casein, found in milk, 

 and forming the main bulk of cheese. 



Fats belong to the organic compounds in the body 

 which contain no nitrogen ; they consist solely of carbon, 

 hydrogen, and oxygen. The chief fats in the body are 

 palmatin, stearin, and olein ; by proper treatment each 

 can be split up into glycerine and a fatty acid; palmitic, 

 stearic, or oleic acid as the case may be. 



What is found in addition in some of them ? How many chief 

 varieties of organic compounds are there in the body? Name them. 



Give another name for albuminous substances. Can they be made 

 artificially? Give an example of an albumen. What elements do 

 albumens contain ? Name the more important albumens of the body ? 

 Where are they found ? 



What elements do fats contain ? Name the chief fats of the body. 

 Into what may they be decomposed? 



