62 BOTANY PART i 



boiled in water. The green chlorophyll pigment is also soluble in ether, fatty 

 and ethereal oils, paraffin, petroleum, and carbon disulphide. The alcoholic 

 solutions are fluorescent and appear green in transmitted light, blood red in 

 reflected light. When an alcoholic solution of chlorophyll is shaken up with 

 benzole, the latter, as KKAUS first showed, on standing rises to the surface as 

 a green solution, leaving the alcohol yellow. 



According to MAHCHLEWSKI and ScHUNCK( 41 ), two green pigments are to be 

 detected in the alcoholic extract from leaves. The one, true chlorophyll, is always 

 present ; the other, which has been termed allochlorophyll, cannot be detected in 

 some plants. The yellow pigments of the chloroplasts are collectively termed 

 xanthophyll. Only chrysophyll, which forms shining red crystals, has been 

 isolated ; the rest of the xanthophyll form amorphous masses. True chlorophyll 

 is characterised by three absorption b;inds in the less refrangible half of the 

 spectrum, and three in the more refrangible portion. As yet only one band, 

 which lies in the red portion of the spectrum, is known for aliochlorophyll. 

 The amount of chlorophyll in a green plant is very small. T.SCHIRCH ( 4 -) has 

 calculated that only O'2-l'O gr. of chlorophyll can be obtained from a square- 

 metre of green foliage leaves. 



From the investigations of MARCHLEWSKI and NENCKI it appears 

 that a relationship exists between chlorophyll and haemoglobin (the 

 pigment contained in red blood corpuscles) ( 43 ). 



The green colour of the chlorophyll in some groups of Algae is 

 more or less masked by other pigments. In addition to the chloro- 

 phyll green, with its accompanying yellow pigments, many of the 

 blue-green Schizophyceae contain a blue colouring matter, phycocyanin, 

 while the red Algae possess a red pigment termed phycoerythrin. 

 These pigments are soluble in water, and are characterised by a 

 beautiful fluorescence. The phycocyanin may often be found as a 

 blue border surrounding a blue-green Fission-Alga which has been 

 dried in a press. 



Whether these pigments are mixed with the chlorophyll or are 

 chemically combined with it is as yet undecided ( 44 ). Recently HANS 

 MOLISCH ( 45 ) has attempted to prove that the brown coloration of the 

 Diatoms, the brown Algae, and especially of a saprophytic Orchid 

 (Neottia nidus a?vis), is not due to a mixture of a brown pigment with 

 chlorophyll. He regards it as due on the other hand to a single 

 pigment, phaeophyll, which is nearly related to chlorophyll and 

 readily undergoes a chemical change into ordinary chlorophyll. 



Before the leaves of trees fall in the autumn their cells lose nearly 

 all their cytoplasmic contents, and at the same time the chloroplasts 

 undergo disorganisation. There remains only a watery substance in 

 the cell cavity, in which a few oil globules and crystals, together with 

 a few yellow, strongly refractive bodies, can be seen. Sometimes in 

 presence of abundant sugar this liquid in the cell cavities becomes red, 

 and thus imparts to the foliage its autumnal brilliancy. In the leaves 

 of coniferous trees, which only indicate the approaching winter by 

 assuming a somewhat brownish tint, the cause is different. The 



