[1] Thus the following expression in Galt's "Annals of the
Parish" is justified--"My son Gilbert was seized with the
smallpox and was blinded by THEM for seventeen days."



Smallpox is unquestionably a highly infectious or communicable
disease, and in the language of a past day, there is a virus or
poison which can pass from the sick to the unaffected; when
this transference occurs on a large scale we speak of an
epidemic of smallpox. As Sir William Osler truly says, "It is
not a little remarkable that in a disease, which is rightly
regarded as the type of all infectious maladies, the specific
virus still remains unknown." The same, however, is true of the
common diseases of scarlatina, measles and chickenpox. Of some
diseases, the virus is a bacillus or coccus, excessively minute
fungi recognizable only under the microscope; but the
bacteriologists are now beginning to speak of viruses so
impalpable that they, unlike ordinary bacteria, can go through
the pores of a clay filter, are filter-passers, that is are of
ultra-microscopic dimensions. Some authorities conjecture that
the virus of variola belongs to the group of filter-passers.
The virus of smallpox, however, is very resistant and can be
carried through the air for considerable distances; it clings
for long periods to clothes, books, furniture, etc.

I shall not now digress to give the clinical details of a case
of smallpox; the eruption may be slight or it may be very
extensive. It occurs in three forms, discrete, confluent and