402 ADVANCED PHYSIOLOGY 



Page 43. Cut a raw potato and place some iodine upon the cut 

 surface. Treat a bean that has been soaked in water for a day in the same 

 way. Which shows the more starch? 



By definite trials, prove that egg albumen, meat, flour, and sugar do not 

 react in uniform ways to this treatment. The test is specific for starch. 



Page 45. With a thermometer it will be easy to ascertain the melting 

 point of some fats, e.g. butter, lard, pork fat, and mutton fat ; then com- 

 pare with temperature of the body. 



Page 54. With very sharp razor prepare very thin sections of raw and 

 cooked potato; place under a microscope and demonstrate the points 

 here mentioned. 



Page 55. Prepared slides of pork muscle infected with trichina are 

 obtainable from nearly any dealer in microscopical preparations. Con- 

 sult address list in another part of Appendix for partial list of dealers. 



CHAPTER IV 



Page 63. Fill a test tube half full of a solution of molasses (better 

 than this is Pasteur's solution) and to it add a little yeast from an ordinary 

 yeast cake. Let the mixture stand in a warm place for several hours. 

 CO 2 gas, due to fermentation, will appear as bubbles. To prove the nature 

 of this gas, take a larger amount of the fermenting mixture in a flask, and 

 conduct the gas by a tube, as shown in Figure 26, into limewater; a 

 white precipitate in the latter proves the presence of CO 2 . After a time, 

 the formation of alcohol in the sugar mixture can be detected by its odor. 



To make this demonstration more vivid and complete, the fermenting 

 solution should be put into flask, over opening of which a rubber tube is 

 fitted, this in turn being connected to glass tube which can be led through 

 a stream of water ; then boil the liquid, and the vapor will be condensed 

 in the cold glass tube and thus alcohol can be collected in liquid form. 

 This carries out the principle of a still. 



Page 64. Mix starch and water in a small beaker. Heat, stirring 

 constantly, and note how the mixture thickens owing to the bursting of 

 the starch grains and the absorption of water. 



Place a little of the mixture in a test tube and by the method used in 

 the demonstration for page 31 determine that it contains no sugar. In 

 another test tube mix a small portion of the starch solution with plenty 

 of saliva. Be very sure that the test tube is perfectly clean ; a trace of 

 acid in it will prevent the desired result in this experiment. Place the 

 saliva and starch mixture in a beaker of water. Heat the latter to about 



