THE FLOWEEING PLANT SEEDS 347 



any proteid substances ? Compare the chemical 

 contents of germinating with those of dry seeds. 

 Do you find anything present in the germinating 

 which is not in the dry seed? Bake some dry 

 seeds to destroy their power of germination, then 

 place them in water. Do they still absorb water ? 

 If so, test some of them for starch and others for 

 glucose. Is the formation of glucose in a germi- 

 nating seed due to some chemical change which 

 takes place as the seed germinates, or to the im- 

 bibition of water? Why? 



g. Action of the diastase of malt upon starch. 



Make a thin starch paste by adding to boiling 

 water a few drops of a mixture of dry starch and 

 water. Cool the paste, and to it add a pinch of 

 Merck's diastase of malt, which may be obtained 

 of druggists. Let the test-tube stand in a warm 

 place for a few minutes, then test its contents for 

 the presence of glucose. Do you find any ? Can 

 diastase change starch to grape-sugar? If a di- 

 astasic ferment were present in a plant -cell, do 

 you think that the starch in the cell might be 

 changed to glucose ? 



h. Osmosis. 



Take two dialyzers. Into the inner jar of one 

 put some starch mixed with water ; in^o the in- 

 ner jar of the other put some grape-sugar dis- 

 solved in water. Into the outer jar of each put 

 distilled water. After a few hours test the water 

 in the outer jar of the first dialyzer for starch ; 

 that in the outer jar of the second for grape- 

 sugar. Which dialyzes ? 

 Keview the experiments on the contents of 



