220 SEVENTH REPORT OF THE FOREST, FISH AND GAME commission. 



of the petioles. When the leaf falls and the cell sap evaporates, and the chloro- 

 phyll bodies die, the erythrophyll lays hold of the cell wall and solid contents and 

 stains them. In this way dried leaves retain their red color. As ery';hrophyll is 

 soluble in water, however, contact with moisture will soon cause the most of it to 

 disappear." 



An English writer, Mr. Alfred Russell Wallace, notes that chlorophyll is not a 

 simple. green pigment, but that it really consists of at least seven distinct substances, 

 varying in color from blue to yellow and orange; and that they differ in their 

 proportions in the chlorophyll of different plants, have different chemical reactions, 

 are differently affected by light, and give distinct spectra. He suggests the collec- 

 tive name chromophyll as a proper one for designating the presence of these various 

 pigments. 



Kerner and Oliver in their Natural History of Plants state that "The chemical 

 composition of colouring matters is yet little known, and it is possible that at present 

 a whole group of them is collected together under the name anthocyanin," * and 

 that this substance " appears red in the cell sap in the presence of acids, blue when 

 no acids are present, and violet when the amount of free acids is but small. If there 

 is an abundance of yellow granules together with the acid, red anthocyanin, the 

 leaf assumes an orange color." 



Mr. Justus Watson Folsom, in an article on " Autumnal Changes in Leaves" 

 (Garden and Forest, Vol. VIII, p. 392), says: 



"A green leaf, or an alcoholic extract of one, viewed through a spectroscope, 

 shows a band of light, or spectrum, which is very characteristic ; its dark intervals 

 or absorption bands, resembling those of no other substance. If, now, we mix 

 benzine with our green solution of chlorophyll which we have obtained by soaking, 

 say, elm leaves in alcohol, the liquid separates into two layers, the upper of 

 bluish-green benzine, and the lower of yellow alcohol. These two solutions give 

 different spectra, proving them different substances. Our chlorophyll, then, was 

 a mixture of at least two substances, or, more likely, a chemical compound 

 which broke into two of its constituent compounds, the yellow one being called 

 xanthophyll. Now, this separation presumably occurs when green leaves turn yel- 

 low, as is suggested by a simple experiment. If our alcoholic extraction from elm 

 leaves has not been kept in darkness and sealed from the oxygen of the air, it has 

 rapidly decomposed, turning from green to yellow — that is, the green constituent 

 fades away first, gradually revealing the yellow one, which, by the way, some con- 

 sider the equivalent of the etiolin that always precedes the first formation of the 

 green pigment." 



* From the Greek words meaning flower and blue. 



