nexperienced class of readers addressed.

I. It has been long believed, by many competent observers, that
Puerperal Fever (so called) is sometimes carried from patient to patient
by medical assistants.

II. The express object of this Essay is to prove that it is so carried.

III. In order to prove this point, it is not necessary to consult
any medical theorist as to whether or not it is consistent with his
preconceived notions that such a mode of transfer should exist.

IV. If the medical theorist insists on being consulted, and we see fit
to indulge him, he cannot be allowed to assume that the alleged laws of
contagion, deduced from observation in other diseases, shall be cited
to disprove the alleged laws deduced from observation in this. Science
would never make progress under such conditions. Neither the long
incubation of hydrophobia, nor the protecting power of vaccination,
would ever have been admitted, if the results of observation in
these affections had been rejected as contradictory to the previously
ascertained laws of contagion.

V. The disease in question is not a common one; producing, on the
average, about three deaths in a thousand births, according to the
English Registration returns which I have examined.

VI. When an unusually large number of cases of this disease occur about
the same time, it is inferred, therefore, that there exists some special
cause for this increased frequency. If the disease prevails extensively
over a wide region of country, it is attributed without dispute to
an epidemic influence. If it prevails in a single locality, as in a
hospital, and not elsewhere, this is considered proof that some local
cause is there active in its production.

VII. When a large number of cases of this disease occur in rapid
succession, in one individual's ordinary practice, and few or none
elsewhere, these cases appearing in scattered localities, in patients of
the same average condition as those who escape under the care of others,
there is the same reason for connecting the cause of the disease with
the person in this instance, as with the place in that last mentioned.

VIII. Many series of cases, answering to these conditions, are given
in this Essay, and many others will be referred to which have occurred
since it was written.

IX. The alleged results of observation may be set aside; first, because
the so-called facts are in their own nature equivocal; secondly, because
they stand on in