THE PHYSIOLOGY OF COLOR IN PLANTS. 7 i 



which is discounted, in part at least, by the low figure selected to represent 

 average wages. 



It is apparent that a rearrangement of some kind would be necessary ; is 

 it not likely that this rearrangement would be found in a corresponding 

 reduction of wages ? 



Sympathizing as I do with all legitimate efforts of workingmen to bet- 

 ter their condition, it appears to me that the aim of their organizations 

 should be to secure a reduction in the hours of those workers who are com- 

 pelled to submit to clearly excessive consecutive hours of attention to duty 

 conditions that are not only deleterious to the welfare and happiness of 

 the laborer himself, but in some instances increasing the danger to life and 

 limb of others whose interest and sympathy would be a powerful lever, if 

 properly applied, to help to remove this incubus resting at present upon the 

 boasted freedom of labor in this country. 



If the views which I have here advanced shall have the effect of tend- 

 ing, on the one hand, to discourage unwise and impracticable schemes of 

 some misguided wage-workers, and, on the other hand, to stimulate keener 

 and more general interest on the part of employers of labor in the welfare 

 of their operatives, and thus to foster a closer union between these two great 

 interdependent elements of society, I shall feel that my efforts have been 

 repaid. The nature of my occupation for the past fifteen years has per- 

 haps afforded unusually favorable opportunities for viewing both sides of 

 the sociological questions here discussed ; it has certainly aroused keen per- 

 sonal interest in the subject and has stimulated study of these problems. 



THE PHYSIOLOGY OF COLOR IN PLANTS. 



By D. T. MACDOUGAL, 



ASSISTANT PROFESSOR OF BOTANY IN THE UNIVERSITY OF MINNESOTA. 



THAT the color exhibited by the roots, stems, leaves, and 

 especially flowers and fruits of plants received serious atten- 

 tion at a very early date is well attested by ancient record. It 

 was only in comparatively recent time, however, that the daring 

 conjecture was hazarded that even such an abundant, widely 

 distributed, and characteristic color as chlorophyll (leaf-green) 

 subserved a purpose in the life-process of plants. Doubtless 

 certain masses of marked color, or combination of pronounced 

 tints, must have afforded a gratification to man's sense of beauty 

 quite, early in his development. At the same time and earlier 

 these colors were also used as a distinguishing mark in the 

 selection of plants for food, and later they were taken to be indic- 

 ative of the absence or presence of magical curative properties. 

 The first-named feature is still valid, and forms the basis of the 

 art of the gardener and florist to-day. The last-named aspect of 

 plant colors received its greatest attention during the prevalence 

 of the practices of the Grecian Rhizotomoi and Pharmakopoli, 

 and later in the "doctrine of signatures." The doctrine of 



