44 MANUAL OF GENERAL AGRICULTURE. 



distinction is marked, or where flour from winter and 

 spring wheats can be obtained, treat a sample of each as 

 indicated, and compare the two. 



43. EXTRACTION AND DECOMPOSITION OF 



CHLOROPHYLL. 



Materials: Green leaves, preferably of young grow- 

 ing grass or cereal, large test tube, two small test tubes. 



Place some green leaves into a large test tube, filling 

 the tube about one-third full. Pour alcohol over them 

 until the test tube is about one-half full. Boil for about 

 two minutes. Transfer the liquid to two small test tubes, 

 pouring the same amount into each. Note the color of the 

 chlorophyll extract. 



Place one solution in direct sunlight and the other in 

 complete darkness. At the end of an hour and again at 

 the next meeting compare the two. 



Questions: 1. What is chlorophyll? 2. What is 

 the effect of light on chlorophyll ? 



44. DETERMINATION OF OIL IN FLAXSEED. 



Materials : Ground flaxseed, ether or benzine, evapo- 

 rating dish, filter, filter paper, ring stand. 



(a) Weigh out 25 grams of flaxseed and add 25 c.c. 

 of ether or benzine.* Let stand about fifteen minutes and 

 then filter into an evaporating dish. Wash the meal by 

 pouring over it, a little at a time, about the same amount 

 of ether or benzine. Let the liquid stand in a good draft 

 until the next laboratory period or until it has lost the 

 odor of the liquid used. Weigh the remaining oil (fat) 

 and calculate what per cent of the ground seed was oil. 

 (A small amount of fat will still be left in the residue.) 



(1) Describe the oil obtained. (2) Of what use 

 would it have been to the plant ? 



Optional. Oil from yolk of egg. Repeat the above 

 experiment, using 10 grams of the yolk of a hard-boiled 

 egg and add 10 c.c. of ether or benzine. 



*Do not bring ether or benzene near a flame. 



