CH. Il] CHLOROPHYLL. 45 



copper compound with phyllocyanin is produced, which 

 has the general appearance of chlorophyll, but differs 

 notably in not being fluorescent. To observe this point, 

 compare it with unaltered chlorophyll extract; fluores- 

 cence is most easily visible with a strong solution in a 

 narrow test-tube. 



(60) Stability of the copper compound. 



Fill two test-tubes A, B, with the copper compound 

 and two others C, B, with unaltered leaf-extract : place A 

 and G in sunlight, B and D in the dark. After some 

 hours note by comparison with B and D, that the copper 

 compound is not destroyed while G is affected. 



(61) Spectroscopic examination. 



To see the characteristic chlorophyll band T in the red, 

 a small direct-vision spectroscope may be used: the solution 

 may be in a test-tube, and ordinary daylight will suffice. 

 In Detmer's Praktikum, p. 17, a convenient holder for 

 test-tubes is figured and described. For the other bands 

 direct sunlight is needed, the solution which must be 

 a weak one, should be placed in a parallel-sided vessel, 

 and a more elaborate spectroscope should be used. 



(62) Other pigments. 



The red varieties of Ricinus, Coleus and Amaranthus 

 may be used. In the last named the red colour can be 

 obtainfed by boiling a leaf in water, which takes out the 

 coloured cell sap, and leaves the leaf green. In the case 

 of Ricinus and Coleus the red colour is destroyed by 

 boiling. If these leaves are partly immersed in boiling 



