63. Neutral fats. The neutral fats of the adipose tissue 

 of the body generally consist of a mixture of the neutral 

 fats, stearin, palmitin, and olein, the two former being 

 solid at ordinary temperatures, while olein is fluid, and 

 keeps the other two in solution at the temperature of the 

 body. They are lighter than water : Sp. gr. 0.91-0.94. 



64. Take a little lard or olive oil, and observe that fat is 

 soluble in ether, also chloroform, but insoluble in water. 



65. Take some of the ethereal solution of lard and let some 

 of it fall upon some paper. The ether soon evaporates but 

 a permanent greasy stain is left. 



66. Add caustic potash to olive oil and boil. A glycerin- 

 oleate is formed. 



67. Heat some lard and caustic soda solution in an evapo- 

 rating dish to form a soap, decompose the latter by heating 

 it with dilute sulphuric acid (10 5^0) and observe the liberated 

 fatty acids floating on the top. 



68. Shake a few drops of cod-liver oil with a small amount 

 of dilute solution of sodium carbonate. The mass should 

 become white — an emulsion. In an emulsion the particles 

 of oil are broken up into innumerable finer particles which 

 remain discrete, that is, do not run together. Milk is a 

 typical emulsion. Examine some of the cod-liver oil emul- 

 sion under the microscope. 



69. Bone. Organic basis obtained by decalcification. 

 Place a small thin dry bone in dilute hydrochloric acid (i 

 part of the acid to 8 of water) for a few days. Its mineral 

 matter is dissolved out, and the bone, although retaining its 

 original form, loses its rigidity, and becomes pliable, and so 

 soft as to be capable of being cut with a knife. What re- 

 mains is the organic matrix of ossein. 



70. Wash the decalcified bone thoroughly with water, in 

 which it is insoluble, place it in a solution of sodium carbon- 

 ate and wash again. Boil it in water, and from it gelatin 

 will be obtained. Neutralize it with sodium carbonate. The 

 solution gelatinizes. Test the solution for gelatin. (24-32.) 



