But the physical damage proved far less serious than the physiological. Earnest research discovered, indeed, a means of checking the infection; and, after a few years of rigorous purging the atmosphere and man’s flesh were clean once more. But the generations that had been stricken never recovered; their tissues had been too seriously corroded. Little by little, of course, there arose a fresh population of undamaged men and women. But it was a small population; for the fertility of the stricken had been much reduced. Thus the earth was now occupied by a small number of healthy persons below middle-age and a very large number of ageing invalids. For many years these cripples had contrived to carry on the work of the world in spite of their frailty, but gradually they began to fail both in e
