724 TRANSACTIONS OF SECTION I, 



in the blood, urine, milk, &c., and of thus comparing the functional activity oi 

 organs. Crjoscopy, osmotic pressure, and electrical resistauce. 



2. Observations on Hue Perception. 

 By F. W. Edridge-Green, M.D., F.R.G.S. 



If a small portion of a spectrum be isolated by means of shutters in the eye- 

 piece of a spectroscope, it will be found that when it has a certain magnitude it 

 appears mouochromatic. The size of this monochromatic patch varies according 

 to the portion of spectrum which is being observed and with different persons. 



The perception of hue is least at the ends of the spectrum, and then in the 

 green in the region which possc-sses no ' complimentary ' within the spectrum. 



In some cases the perception is best in the blue region, in others in the 

 yellow. 



