Note 129 — Chapter XI · PEARSON’S EXAMINATION.[128]

Such was the logic, but such was not the fact. If no one could have Smallpox twice, and if inoculated Cowpox was equivalent to Smallpox, no one could have Cowpox twice. Such was the argument. Pearson did not foresee its systematic refutation exemplified in Re-Vaccination, septennial, triennial, annual.