480 



CHEMISTRY OF THE PROTEIDS 



Nature of Light-waves 



CHAP 



The mean visible wave-frequency is about 508 to 510 million million 

 vibrations per second. 



Oxyhaemoglobin 



OxyhcemogloUn possesses three well-defined absorption-bands a, ft. 

 and y, and probably a fourth band in the red, see below. The bands 

 a and ft lie between the Fraunhofer's lines D and E, of which the 

 narrower but more sharply defined band a commences close to D : 



a A5S2-A571 

 ft A550-A526 

 y A424-A404 



The second band /3 reaches, according to Hiifner's spectro-photometric 

 measurements, its maximum intensity between 



A542-5 and A531'5 



It is to the eye less intense than is the band a, but in spectro-photo- 

 metric measurements this is not the case according to Hiifner. The 

 quotient of the absorption coefficients at the place of the maximal 

 absorption in band ft, and at the place of greatest light between the 

 bands a and ft, is according to Hiifner in the case of oxyhsemoglobin 

 1-578. Miiller 1 finds, however, that the quotient of blood freshly 

 drawn from the ears of healthy dogs is frequently as low as T47 to 

 1*48, and warns against implicit faith in Hiifner's figures, which 

 were obtained from purified oxyhsemoglobin crystals. [See later, 

 p. 482.] The third band y, of about the same intensity as band ft, 

 reaches its maximum intensity at A414, close to the line h. The 



1 Franz Miiller, Pflugers Arch. 103. 541 (1904). 



