474 MAMMALIA— PHYSIOLOGY 



spinal nerves. Its fibers are called white rami communicantes 

 (medullated) and gray rami communicantes (non-medullated). 

 Sense Organs. — 



Kulpe's Classification of Sensations by Organs i" 

 1. Vision, 

 1. Audition. 



3. Cutaneous. 



Cold 

 Warmth 

 Pressure 

 Pain 



4. Olfactory. 



5. Static sense. 



Ampullar (dizziness) 

 Vestibular 



6. Gustatory. (See page 477.) 



7. Kinaesthetic. 



Muscular 



Tendinous 



Articular 



8. Organic. 



Hunger 

 Thirst 

 Nausea 

 Suffocation 



9. Reproductive. 



Vision depends on the proper function of the complicated eye. 

 Sensation passes from the layer oirods and cones of the retina through 

 its nuclear and molecular layers to the ganglion cells from which 

 nerve fibers transmit the impulse to the optic tracts leading to the 

 brain. (See p. 468.) 



Visual sensations include hue or quality, brightness and satura- 

 tion. The stimuli are the ethereal vibrations ranging between 

 400,000 and 800,000 billions per second. Color is stimulated 

 by the wave length while the height of the wave gives the bright- 

 ness and the form of the wave determines the degree of saturation. 

 ■It is said that in certain tapestries in Milan there are 1,800 colors 

 while in some Italian mosaics there are 30,000 colors. ^^ 



Color Blindness. — Some people are unable to distinguish all of 



1° Consult Murchlson, C. 1929. The Foundations of Experimental Psychology. 

 Clark Univ. Press. 



11 Consult Herrick, C. J. 1931. Introduction to Neurology. W. B, Saunders. 



