Even though part of the energy of the incident light is probably absorbed by chemical entities which play no part in the specific reaction of inactivation, nevertheless the wave lengths most active in destroying biological cells or agents will presumably be found to be among those absorbed in the highest proportion. This would indicate that the curves here presented are approximately reciprocal to the coefficients of absorption of particular substances, the destruction of which caused the inactivation of the agents or the death of the cells. The similarity between the curves for bacteria, virus, and phage, both in shape and in total involved energies, suggests the presence of a common factor, or of closely related chemical entities, sensitive to ultra-violet light, whereas the data for the tumor agent suggest that its inactivation is due to the destruction of a substance having an essentially different spectral absorption, and therefore of a different chemical character. While the amount of ultra-violet energy required to affect the tumor agent is great, it is still less than that involved in the inactivation of some of the enzymes (7).
A study is under way to compare the deduced spectral analysis with the actual coefficients of absorption of the highly purified tumor agent.