Then it occurred to Sir James that light–the strangely active ultra-violet rays of light–might be able to disintegrate and destroy the bacteria, even when frozen solid at the lowest temperature. He exposed his frozen cultures to strong light, excluding any heat-giving rays, and found that the bacteria no longer recovered when subsequently the culture was thawed. Light, certain rays of light, can, it thus appears, penetrate and cause destructive vibrations in chemical bodies protected from all other disintegrating agencies by the solidity conferred by extreme cold. I am not able to say, at the moment, how far this important matter has been pursued by further experiment, nor whether what are called the "chemically active" rays of light and other rays such as the Röntgen rays can effect chemical change in other bodies (besides living germs), upon which they act at normal temperatures, but in regard to which they might be expected to be inoperative when the bodies in question are brought into the peculiar state of inactivity produced by extreme cold. Since light is far more intense outside our atmosphere than within it, it seemed, at first, that the demonstration of its destructive action on frozen germs puts an end to Kelvin's theory of a meteoric origin of life. It must, however, be remembered that minute living germs could conceivably be protected from the access of light by being embedded in even very small opaque particles of meteoric clay. So Lord Kelvin's suggestion as to the travelling of life on meteoric dust cannot be set aside as involving the supposition of the persistence of life in conditions known to be destructive of it. The great interest in former times in relation to "suspended animation" has naturally been in relation to the occurrence of this condition in man and the possibility of producing it in man by this or that treatment. There is no doubt whatever, at the present day, that "death-like" trances, whether occurring naturally or after the administration of drugs, in the case of man and of higher animals, are not due to that complete suspension of living changes which we can produce, as I have here related, in certain lower forms of life. These death-like trances are merely cases of reduction of the living changes to a very low degree.[6]