Kraemer : Color in plants 83 



brown in the brown algae, etc. The color-substances are more or 

 less difficult to extract. The chlorophyl can be extracted by the 

 use of absolute or 95 per cent, alcohol, except in the case of some 

 of the more delicate red forms like Grijfithsia, Dasya, Grinnelliq, 

 Callithamnion, Agardhiella, etc., w r here it is necessary to place the 

 material direct from sea-water into a saturated solution of sodium 

 chloride and afterwards treat with alcohol. 



While the red and brozvn color-substances are for the most part 

 difficult to extract, still some of them can be extracted quite easily 

 with water or dilute alcohol, and these show an analogy in their 

 behavior toward reagents to the cell-sap color-substances of the 

 higher plants. 



It would appear from a microscopical study of the marine algae 

 that all the color-substances arise in the plastids. The difficulty 

 in extracting these substances in most cases leads to the supposi- 

 tion that either owing to the composition of the plastid or of the 

 cell-sap, the color-substances are held by the plastids and not dif- 

 fused in the cell-sap as in the higher plants, i. e. f the cell-sap color 

 is held in the vacuolules of the plastids. 



Preservation of plant specimens 



The fact that the red and brown coloring substances of these 

 marine algae were held back or rendered insoluble by the use 

 of a saturated solution of common salt, suggests the use of this 

 solution as a preservative of not only marine algae, but also of 

 fruits, flowers and vegetables for study or exhibition purposes. 

 Specimens have been preserved in this manner, some of them for 

 more than a year. I may add, however, that not all specimens 

 can be preserved with salt solution. 



plants 



That the color in plants is influenced by a number of factors, 

 including light, temperature and soil, is well known. One of the 

 most common examples showing the influence of light is furnished 

 by certain sorts of apples, those portions of the fruits exposed to 

 the direct sunlight being most highly colored. The influence of 

 temperature on the color of plants is also illustrated by the highly 

 colored red apples of higher latitudes. It is a matter of general 



