May 6, 1904.] 



SCIENCE. 



727 



with a protoplasmic body termed by the 

 author an etioplast. These bodies are more 

 or less spherical or polygonal and are about 

 one thousandth of a millimeter in diam- 

 eter. They occur in the cells beneath the 

 epidermal layer, and later, under the in- 

 fluence of light, appear to be transformed 

 into chloroplasts, the bodies giving the color 

 to the leaves and other green parts of the 

 plant. Under certain conditions the 

 chloroplastid may likewise undergo a trans- 

 formation into a yellow orange-colored 

 body, known as a chromoplast, the pigment 

 associated with it being called by the au- 

 thor, chromophyl. These plastid pigments 

 are distinguished from all other plant 

 colors by their solubility in such solvents 

 as benzol, ether, volatile oils, etc. 



During the course of metabolism the 

 plant cell manufactures other color sub- 

 stances which are not combined with the 

 protoplasm or other organized bodies, but 

 which are contained in the cell sap or liquid 

 of the cell. These substances, unlike the 

 plastid colors, are insoluble in the above- 

 named solvents, but soluble in water and 

 alcohol, which affords a means of separa- 

 ting them from the plastid colors. Most 

 of the colors of flowers excepting yel- 

 low and orange are due to substances 

 of this class. The colors of many fruits, 

 as apple, cranberry, strawberry, black- 

 berry, grape, etc. ; of red and brown sea- 

 weeds; of vegetables, as turnip, radish, 

 rhubarb, purple cabbage, etc., and also 

 of autumn leaves belong to this class, 

 that is, are cell-sap colors. The author's 

 experiments tend to show that the color of 

 autumn leaves, as beech, maple, oak, etc., 

 are in the nature of cell-sap colors, rather 

 than due to a compound associated with the 

 plastids as has been supposed heretofore. 

 His researches, furthermore, tend to show 

 that there is considerable difference in the 

 cell-sap colors, or dyes, from various plants, 

 and while they are all more or less constant 



in their behavior toward sodium phosphate, 

 yet their behavior, with a dozen or more 

 reagents shows that no two of them are 

 precisely alike, or if they are alike are asso- 

 ciated with substances which influence their 

 behavior toward reagents. As illustrating 

 this point it may be mentioned that while 

 the color of red rose closely resembles that 

 of the red portion of the turnip in many 

 respects, it differs from it in that an alco- 

 holic solution of red rose becomes cloudy 

 or fluorescent on the addition of water and 

 the color is intensified on the addition of 

 salicylic acid. It is also interesting to note 

 that in the kernel of black Mexican sweet 

 corn contiguous cells may show different 

 colors, as reddish, bluish-green and pur- 

 plish, this being due to the nature of the 

 other substances associated with the dye in 

 the cell sap. 



The author is inclined to look Upon the 

 chromoplastids of both flowers and fruits 

 as having the special function of manu- 

 facturing and storing nitrogenous food 

 materials, which are almost invariably con- 

 tained in them, for the use of the germin- 

 ating plant. He further considers the cell- 

 sap colors, like other organized cell-con- 

 tents, to be incidental to physiological ac- 

 tivity and of secondary importance in the 

 attraction of insects for the fertilization of 

 the flower and dispersal of the seed. 



SATURDAY, APRIL 9. 



Morning Session — 10 o'clock. 

 President Smith in the chair. 



The Establishment of Game Refuges in the 

 United States Forest Reserves: Mr. Al- 

 DEN Sampson, Haverford, Pa. 

 The author spent six months in the 

 forest reserves of California and Washing- 

 ton, during the summer of 1903, as game 

 preserve expert, sent out by the United 

 States Biological Survey to study the prob- 

 lem of game refuges, and to select tracts 



