The Intake of Carbon 203 



solutions as may be conveniently obtained. The solution 

 is fluorescent by reflected light, and it is rapidly decom- 

 posed in strong light. 



The chlorophyll pigment as extracted is a mixed sub- 

 stance. Two products which are constant and predomi- 

 nant permit of partial separation through their diverse 

 relations to solvents. Thus if benzole is added to the 

 alcoholic solution and the latter vigorously shaken, there 

 will result on standing a blue-green benzole layer and a 

 yellow alcohol layer. There are therefore two substances, 

 a blue-green one which has passed largely into the benzole, 

 and from the color it is usually called blue chlorophyll 

 or cyanophyll; while the yellow substance remaining in 

 the alcohol is mostly carotin. 



Apparently cyanophyll does not exist alone in nature. 

 It is a complex molecule containing nitrogen, and is vari- 

 ously supposed to have phosphorus or magnesium associ- 

 ated or combined with it. Cyanophyll is closely related, 

 it would seem, to the haemoglobin of blood ; and it yields 

 a variety of decomposition products, some of which col- 

 orimetrically and chemically seem to be identical with 

 certain products of haemoglobin. 



Carotin is of common occurrence in a variety of colored 

 tissues, and in its crystalline form it is most conspicuous 

 in the root of the carrot and in the petals of certain orange 

 or yellow flowers. This pigment belongs to the group 

 often called xanthophyll. The term "etiolin" is also ap- 

 plied to it. The substance is present in etiolated organs, 

 and it may long persist in the chloroplasts of leaves during 

 the autumn. 



The most important property of chlorophyll is its ca- 



