1904. J KRAEMER — NATURE OF COLOR IN" PLANTS. 267 



In addition I desire to say that I am inclined to look upon the 

 chromoplastids of both flowers and fruits as having the special 

 function of manufacturing or storing nitrogenous food materials, for 

 the use of the developing embryo or developing seed, particularly 

 as protein grains are usually contained in them. The same may 

 be said of the chromoplasts in roots, as in carrot, where the pro- 

 teids of the chromoplasts are utilized by the plant of the second 

 year. 



I am further inclined to consider the cell-sap colors, like other 

 unorganized cell-contents, as alkaloids, volatile oils, etc., to be 

 incident to physiological activity, and of secondary importance in 

 the attraction of insects for the fertilization of the flower and dis- 

 persal of the seed. 



Finally, I acknowledge my indebtedness to Miss Florence Yaple, 

 Philadelphia, for valuable assistance in the preparation of this 

 paper. 



Bibliography. 



1. Dippel: Das Mikroskop, 2te Auflage, zweiter Theil, erste Abtheilung, 



pages 65 and 66. 



2. Pringsheim: " Untersuchungen liber da.s Chlorophyll,'^ Mona^sdericA^i der 



Kdniglich Preussischen Akademie der Wissenschaften zu Berlitty 1874, 

 p. 628. 



3. Mueller: " Spectralanalyse der Bluthenfarben," Pringsheini's Jahrbuch, 



Bd. XX (1889). 



4. Kraus : «< Ueber die Bestandtheile der Chlorophyllfarbstoffe und ihrer Ver- 



wandten," Sitzungsber. d. med. phys. Gesellsch. in Halle (1871). 



5. Hansen: ^^ Farbstoffe des Chlorophylls,'' 1888, quoted by Dippel. 



6. HusEMANN, A.: Die PJlanzenstoffe, 2te Auflage, p. 959. 



