1 6 Instinct and Intelligence 



energy changes, and thus capable of taking up 

 energy in one form and transmuting it readily 

 into another. For example, when a healthy 

 plant is excluded from that form of energy 

 which we call sunlight, its green leaves lose 

 their colour, but if this plant is removed into the 

 light the protoplasmic elements of some of its 

 cells undergo changes which result in the re- 

 appearance of the natural green colour of the 

 leaves. 1 This colouring matter is contained in 

 what are known as chlorophyll bodies or cor- 

 puscles, the basic substance of which is derived 

 from the living matter of the protoplasm of the 

 cell in which the chlorophyll appears. Our 

 chief interest in these green corpuscles is, their 

 elements are so arranged that they act as 

 specialised energy-transformers. Chlorophyll 

 corpuscles if treated with alcohol soon lose their 

 green colour; the chlorophyll being dissolved 

 out of them by the alcohol, there remains a 

 colourless corpuscle which gives the reaction of 

 proteid substance, and is doubtless of a proto- 

 plasmic nature. The chlorophyll is not actually 



1 Pro^. B. Moore on The Origin a.id Nature of Life, pp. 178, 

 183. Also Lectures on tht Physiology of Plants, by S. H. Vines, 

 PP- 153. 157- 



