476 BIOLOGY. 



2915. Understanding is microcosm, reason macro- 

 cosm. From what is intelligent we expect human wis- 

 dom, from what is rational world- wisdom. 



2916. That the light also has a medium, whereby it acts 

 upon us, is at once evident from our existing in such a 

 medium ; but it could also act directly upon us, were it 

 not inevitably broken up beforehand into colours in tra- 

 versing the media. All terrestrial elements may be a 

 medium for the transmission of light, such as the gaseous, 

 fluid, and solid, i. e. if they are transparent. 



2917. We perceive only coloured light, because our 

 organ of light is only a rigidified colour, a material light. 

 There is no pure light for us ; there is none also in 

 general. 



2918. Sight is thus a terrestrial light-tension, a colour- 

 becoming. 



2919. This happens only through refraction. The 

 eye is a refracting medium. It is distinguished from the 

 brain by being a translucent, refractive, encephalic sub- 

 stance. 



2920. Light does not stream into the eye like water 

 into the sponge, but it progresses gradually into and 

 operates upon it. 



2921. The eye, in order to experience the sensation of 

 light, is placed in a similar tension to the air, water, or 

 crystal. This tension between it and the brain is per- 

 ceived by the latter as illumination. The eye is a prism, 

 in which the brain sees the world, in which the brain 

 observes its own tension, or the production of colour. 

 Sight is a deoxydation of the eye. 



2922. The optic nerve is an organized ray of light, the 

 brain an organized sun, the eye an organized chromatic 

 sun or rainbow. 



2923. Just as the sonorous figures are delineated in 

 the ears, and as the nerve perceives these, but not any 

 concussion of the air ; so also does the optic nerve per- 

 ceive not the light in general, but its terrestrial formation 

 or the chromatic image, which has been propagated into 

 the eye. 



2924. In an eye, while seeing, the world is depicted; 



