90 PHILOSOPHICAL NOTE* ON BOTANICAL SUBJECTb. 



Our very blood is of a brilliant colour, although it is in total 

 (Inrkness, unless let out. It is true that on our lips and our skin 

 lio-ht may penetrate it, but we cannot pretend to assert that light 

 psnetrates the blood of the black bear, with its thick covering of 

 black hair. The blood of the mother does not mingle with that of 

 the foetus, yet that of the latter, although in total darkness, develops 

 its red colour. 



We cannot say that colour is a physiological phenomenon. 

 For in the melons and other allied cucurbits, we find red, orange, 

 yellow, and w^hite coloured pulp, with yellow, red, or black seeds. 

 There may be some physiological difference in these variously 

 coloured pulps, but it is impossible to look upon this difference as 

 of any importance in fruits so closely allied. 



There wa^ another notion, viz., that the greenness of foliage is 

 an indication of health in plants, and of great importance to them, 

 but in the Coleus and Caladiuni foliage, there is often not a particle 

 of o-reen colour. If we can have healthy petals of all colours, it 

 stands to reason that we could have healthy foliage of all colours, 

 even blue, if we could only produce it. 



We can exclude light and still have colours. We cannot, 

 however, exclude electrical influence, which traverses solid opaque 

 bodies, and reaches the darkest recesses of a fruit, or any other 

 body. And, for all we know, it may be this electrical influence, 

 whether it comes from the sun, or from other sources, which 

 brings about the chemical changes, which result in the colours we 

 see ; and with chemical changes, physiological changes will follow. 



The student of colour in plants may derive interest from 

 Capt. Abney's book on " Colour Measurement." He makes out 

 that the primary colours are red, green, and violet, and not red, 

 blue, and yellow, as artists thought. As green is a universal 

 colour among plants, the green leaf may possibly be not only the 

 foundation of all form in plants, but also the foundation of all 

 colour. Red in leaves and bracts is a common colour. And many 

 of the young leaves of plants, such as the Rose, the Mango, Jonesia, 

 and many others are of a reddish or purplish brown. From green, 

 with a mixture of red or violet, all the innumerable shades of colour 

 in plants may be manufactured. 



