Small-pox is not an increasing malady; it is generally introduced here from the slave cargoes of vessels detained by the squadron, and sent here for adjudication; were this source of its renewal removed, I am persuaded that small-pox would, in the course of a few years, be almost unknown in this part of Africa.

  8th.  Can the vaccine virus be retained on points and glasses, so as
  to be fit for use?

The vaccine lymph, if taken on points, will not retain its virulence seven days in this country:  this observation is established by repeated trials; if taken on glasses, I would not be disposed to depend on its activity when kept longer than fourteen or sixteen days, though I have known it sometimes to retain its original properties for four or five weeks; if preserved in glass bulbs, hermetically sealed, in the manner practised by the National Vaccine Institution, I have known its properties unimpaired after keeping for three months; repeated trials have convinced me of the excellence of this mode of preserving the vaccine lymph, and, I believe it to be the best and surest that has been yet devised of transmitting the lymph from England to tropical countries:  next to this method, I believe the crusts have proved the most successful.

  9th.  Are the young negro population pitted with the small-pox?

  The negro population are pitted with the small-pox in the same
  manner as Europeans.

  10th.  Are there periodical vaccinations of large districts? or, is
  each child vaccinated soon after its birth? if the latter, how soon?

The practice, in these cases, is, as long as the vaccine lymph continues to produce a genuine disease, to keep it up by the weekly vaccination of all comers.  Children are rarely vaccinated under four weeks old; but there is no rule observed on this head.

  11th.  What sort of scars are usually left in the arms?

The scar bears the shape of the original vesicle, and is slightly depressed below the surface of the surrounding skin; the surface of the scar is marked by a number of small depressions of various shapes, corresponding, I believe, with the cells in the original vesicle.

  12th.  Is vaccination, in hot countries, attended with feverish
  symptoms? and, if it is, on what day do they begin?

Vaccination is, sometimes, in this country, attended with feverish symptoms; but, in the most marked cases, so far as I have seen, these symptoms have been so slight, as almost to escape common observation.  I have not remarked on what day they begin.

  13th.  Is vaccination ever followed by any eruptions?

  I have seen only one case of this:  an eruption appeared on the sixth
  day after unsuccessful vaccination; it was diffused over the whole
  body, and is now in progress.

  W. FERGUSON, Assistant Surgeon, Royal African Corps.