176 



INACTIVATION OF COMPLEMENT BY LIGHT 



were always the same ones) was occupied by 5 per cent complement. 

 The ratio of the velocities of photoinactivation in the inner tube 

 in the two cases is the same as the ratio of the intensities of the light 

 incident on the inner tube in the two cases, or in other words, since 

 the salt solution absorbs a negligible amount of light, as the ratio 

 of incident to emergent light when the complement is in a layer 1.6 



TABLE II. 



The Efficiencies in Per Cent and Velocities of Inaciivation of Paired Samples of 



Complement, One Sample of Each Pair Being Radiated through a Layer of 



Complement and the Other through a Similar Layer of Balanced 



Salt Solution. 



* In the last column are given the absorption coefficients, M, calculated from 



the formula M = ~r .In — ; where J = thickness of the absorbing layer in centi- 

 dc I 



meters, c = concentration of absorbing substance, and Jo and / incident and 



emergent light intensities. 



mm. deep. Four trials were made and the corresponding absorption 

 coefficients calculated as shown in Table II. In calculating the veloc- 

 ities of reaction, as in the case of Table I, the reaction is supposed 

 to follow a monomolecular course. The rather great divergence 

 between the four observed values is probably explained by variations 

 in the amount of pigment in the different samples of serum. 



