Dr. Jules Guerin, Paris.

A large number of medical men consider a general vaccination and revaccination to be in itself one of the causes of small-pox; a crowd of the newly vaccinated to be itself a dangerous centre of infection; and the 150,000 revaccinations in Paris during the siege to be in some degree responsible for the great epidemics of 1870-1.—Address before the French Academy of Medicine, 1881.