Note 6 — Chapter VII · THE MARCH OF SCIENCE

When we completely understand the nature of the infective and contagious diseases it seems well within the bounds of possibility that the systematic destruction of their germs may be carried far enough to remove them altogether from the planet.6 We have now, even by the highly imperfect measure of quarantine and a period of muzzling (from which, on no evident ground except that it would interfere with the amusements of the governing class to include them, sporting dogs were excluded), apparently banished hydrophobia from Great Britain. If it prove to be the case that just as hydrophobia cannot arise spontaneously, but requires to be “started” by the entry into the blood of an animal of an existing infection, other infective diseases require pre-existing disease before they can arise, we may get rid of them altogether. The dream may appear a wild one. But it is not wilder than the dreams of a thinker who anticipated any one of a hundred common facts of to-day must have appeared to our great-great-grandfathers.