534 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. LX. 



The following papers were read : — 



An attempt to Classify Common Plant Pigments, 

 WITH SOME Observations on the Meaning of Colour 

 in Plants. By Miss M. J. Newbigin, B.Sc. (Lond.). 



It must be obvious to all who have followed the con- 

 temporary literature of pigments, that although there has 

 been in many cases a lavish amount of experimentation, 

 there is as yet little definiten^iss of knowledge. This is 

 especially true in the case of the pigments of plants, 

 where, for example, we find that the literature of chloro- 

 phyll is, even to a German eye, " Sehr umfangreiche," and 

 yet exact results are few. Apart, however, from the 

 general tendency to assume that all plant pigments are 

 derivatives of chlorophyll, and most animal ones derivatives 

 of haemoglobin, there has undoubtedly been accumulated a 

 mass of facts on the subject of chromatology. The present 

 paper is an attempt to collect and systematise the known 

 facts as to the pigments of plants, and to view them from 

 the standpoint of the biologist rather than from that of the 

 botanist proper. 



We will take up first the lipochrome pigments, not on 

 account of their functional importance, for of this nothing 

 is known, but because they are common, readily recognised, 

 and form a convenient starting-point. The lipochromes, 

 or fat pigments, are known through the researches of Kiihne 

 (10), Krukeuberg (9), and others, and are characterised by 

 the combination of the following characters : — They are 

 insoluble in water, but are soluble in alcohol, ether, 

 chloroform, benzol, turpentine, carbon disulphide, etc. In 

 the dry condition they are coloured blue by the addition 

 of concentrated sulphuric or nitric acid. They are very 

 readily destroyed by light, yielding cholesterin or some 

 similar body. Their colour varies from yellow to red ; 

 they contain only carbon, oxygen, and hydrogen, and are 

 usually found associated with fats. They usually give a 

 spectrum of one, two, or three bands in the blue or violet. 

 Although the above characters enable us to recognise the 

 lipochromes very readily, their chemical nature is as yet 



