70

The percentages shown by the medical officer, Sappers and Miners, Madras,
are 77.77, 78.57 and 65.67 respectively ; these results are, I am glad to say, not
approached by the revaccinations performed in this division, which however
appear to me, as regards vaccination, to point out the necessity of a most
watchful care being taken in securing perfect lymph, from carefully selected vesi-
cles ; for it had been observed by an authority that the protective power of vacci-
nation has been " impaired to an incalculable extent by imperfect vaccination" ;
and Jenner himself said that " there may exist every gradation in the state of a
pustule, from that slight deviation from perfection which is quite immaterial, up
to that point which secures no protection at all."

                                                            T. B. JOHNSTONE, M.D.,

                                                                              Deputy Surgeon General.

4th September 1873.