166 ANIMAL LIFE 



at least better than standing on level ground and view- 

 ing the occurrence of colour as a miscellaneous and 

 unrelated display. 



We see that yellow is a sort of ground colour, from 

 which the red blood-pigment emerges as a later wash. 

 To the former we attribute a nutritive value ; it is 

 the harvest colour. To the latter a fiery touch ; it is 

 the carrier of oxygen and the seat of life. 



Movement, that significant attribute of animals, 

 lias obscured the meaning of the one and inereased 

 the value of the other. By creating appetite and 

 capacity, activity lias demanded more nourishment 

 than the yellow pigment could produce, and move- 

 ment has annulled that stationanness and exposed 

 habits that favour its synthetic power in the presence 

 of light, and in general we only see such yellow pigment 

 in tlie inward parts of animals. 



The red colour of blood lias likewise iled the surface 

 and become an internal pigment, bringing the air from 

 the skin, lungs, and gills to the tissues of the whole 

 body. 



On the bare surface so created painting has been 

 done by a later hand, and with old pigments worked 

 up into new combinations. 



The blood, for instance, is worked up into reds 

 and browns; from the liver come the green pigments 

 that we recognise as biliary accomplishments ; and 

 even from remoter and baser organs colouring matters 

 are formed. 



We know thai the skin possesses an eliminating 



