828 



SCIENCE 



[N. S. Vol. XXIX. No. 751 



An account of the brain weight records that 

 have been collected at the Wistar Institute of 

 Anatomy. After the fifteenth year up to the fifty- 

 fifth, the human brain loses slightly in weight 

 and then more rapidly after that period. This 

 slight loss in weight between the fifteenth and 

 fifty-fifth years is attributed to the influence of 

 those diseases which ultimately end in death. 



A'ew; Evidences as to the Physical Basis of Hered- 

 ity: Professor Edwin Geant Conklin, of 

 Princeton. 



Home Notes on the Modifications of Color in 

 Plants: Professor Henet Kbaemee, of Phila- 

 delphia. 



The problem of modifying plants in a particular 

 airection is attended with much difficulty, yet we 

 see in nature numerous modifications which are 

 due to the environment, or to external factors, 

 although it is claimed by some modern evolution- 

 ists that none of the modifications due to food or 

 to change of locality are permanent. 



After reviewing the previous work on the con- 

 trol of color in plants, and enumerating the fac- 

 tors which influence the color in flowers, the 

 author gave the results of his own experiments, 

 which were begun in the autumn of 1904 and have 

 been continued up to the present time. Various 

 soils were experimented with, including an arti- 

 ficial soil, and sand to which a special nutrient 

 was added. The chemicals used to modify the 

 color principles were supplied to the plants in the 

 form of solutions of varying strength, or added 

 to the soil in the solid form, solution gradually 

 taking place. 



Results with Roses. — ^Probably the most stri- 

 king result which the author obtained by the use 

 of chemicals was the production of a red color in 

 the petals of the white rose, Kaiserine. The red 

 pigment occurred in the basal portion of the 

 petals, and was produced in the flowers of plants 

 which were supplied with potassium hydrate, 

 potassium carbonate, calcium hydrate and lead 

 acetate. It should be stated in this connection 

 that the Kaiserine rose tends to yellowish but not 

 to pink or red, and therefore the red color pro- 

 duced in the petals is a new character. Two 

 explanations for its occurrence are suggested: 

 ( 1 ) either the added chemical has reacted directly 

 with a compound already present in the petals, 

 or has induced the formation of an entirely new 

 substance; or (2) the color substance formed in 

 other parts of the plants, as in the leaves, has 

 been transported to the petals through the influ- 

 ence of the chemical. 



Results with Hydrangeas. — Since July, 1907, 

 the author has been experimenting with the red- 

 flowering form of Hydrangea [H. Otaksa) . The 

 following results have been obtained: Blue flowers 

 were produced by plants growing in both sand 

 and garden soil when supplied with the following 

 chemicals: potassium and aluminum sulphate, 

 aluminum sulphate and calcium hydrate. In 

 those plants which were grown in sand and which 

 were supplied with nutrient and potassium car- 

 bonate, blue flowers were also produced. 



The flowers remained pink or red either when 

 growing in soil or when growing in sand and fed 

 with nutrient and supplied in addition with iron 

 and ammonium sulphate, or lead acetate. In the 

 plants fed with lead acetate the original color 

 was considerably intensified. 



In the case of the plants growing in soil and 

 supplied with potassium carbonate there was no 

 change in color, that is, the flowers remained pink, 

 due probably to absorption of the chemical, while 

 as noted above the flowers were changed to blue 

 when growing in sand and supplied with this 

 chemical. 



Comparative Leaf Structure of the Neio Jersey 

 Strand Plants: Professor John W. Haesh- 

 BEBGEB, of Philadelphia. 



Professor Harshberger classified the fioral zones 

 of the New Jersey coast district into four regions 

 or " formations " ; ( I ) the beach, ( 2 ) the sand 

 dune, (3) the thicket and (4) the salt meadow 

 formations. The character of the flora of each 

 region was dwelt upon, and the leaf structures of 

 the plants adapted to each habitat were described 

 and illustrated. Professor Harshberger believed 

 that studies of this character were necessary to 

 indicate what kinds of plants woultt have to be 

 grown, if an attempt to reclaim these regions 

 were to be made. 



The Composition of Chrysocolla: Professor Habbt 



F. Kjelleb, of Philadelphia. 



Under this head are included various hydrated 

 silicates of copper, which are amorphous and of 

 rather indefinite composition. The color of these 

 varies from green to blue. The author described 

 a well-characterized variety from Chile, which 

 forms enamel-like crusts of turquoise blue color, 

 having the composition of an acid silicate with 

 two molecules of water of crystallization. He 

 expressed the opinion that the variation in color 

 must be ascribed to the diiferences in the amount 

 of water of crystallization, the blue varieties con- 

 taining two molecules while the green varieties 

 contain but one. He is also of the opinion that 



