obstacles, and to
place the experiment on a firm basis. The general testimony of all the
facts which they have collected tends really to prove that when the
administration of arsenic is begun some weeks before the presumed season
for the appearance of the fever, and when it is continued regularly
throughout the whole of this season, the power of resistance of the human
organism to malaria is increased. Many individuals gained thereby a
complete immunity, others a partial immunity, that is to say, they were
sometimes attacked by the fever, but it never, even in very malarious
districts, assumed a pernicious form, and was easily subdued by very
moderate doses of quinine. Last year, for example, in the district of
Borino, where the malaria is very severe, M. Ricchi experimented upon
seventy-eight employes of the southern railroads, dividing them into two
equal divisions, one of which received no prophylactic treatment, while
the other was submitted to a systematic arsenical treatment. At the end of
the fever season it was found that several employes among the first half
had been attacked by fevers of a severe type; while thirty-six of those in
the second division had enjoyed a complete immunity, the three others
having been attacked, but so lightly that they cured themselves by quinine
without seeking medical aid.

Facts of this sort are very encouraging, and the more so as the general
health of those submitted to the prophylactic treatment was much improved.
It was found almost invariably, upon the termination of the experiment,
that there had been an increase in bodily weight and an amelioration of
the anaemia which is so common in milarious districts. But, in order to
arrive at such results, it is necessary to be at once bold and prudent. On
the one hand, it is necessary to graduate very carefully the daily dose,
never exceeding at the commencement the dose of two milligrammes (3/100
grain per diem) for adults, and never giving the arsenic upon an empty
stomach. On the other hand, it is necessary to gradually push the dose up
to ten or twelve milligrammes (15/100 or 18/100) a day for adults, in
districts where the malaria is very severe, giving the arsenic in such a
way that there is never an accumulation of the drug in the stomach. Most
of the experiments which have been undertaken this year are being
conducted on this plan, and there is reason to hope that they will give
satisfactory results.

We must not, however, r