PREFACE.

THE following pages are intended to convey to the
reader a concise account of the technical procedures
necessary in the study of bacteriology, a brief descrip-
tion of the life-history of the important pathogenic
bacteria, and sufficient description of the pathological
lesions accompanying the micro-organismal invasions
to give an idea of the origin of symptoms and the
causes of death.

The work being upon Pathogenic Bacteria, it does
not cover the whole scope of parasitology, and the
parasites of higher orders are all omitted. Malaria and
amebic dysentery are omitted as logically as tape-worms
and pediculi. The higher fungi are also omitted, both
because they are not bacteria and because their proper
consideration would make a small book in itself.

In leaving out the non-pathogenic bacteria of course
a stumbling-block was encountered. The Sarcina ven-
triculi, for instance, may be a cause of dyspepsia, yet
"can scarcely be regarded as pathogenic, and, together
with other similar bacteria of questionable deleterious
operation, has been omitted; on the other hand, it
has been thought advisable to include and describe
somewhat -at length a long list of spirilla similar to,
and probably closely allied with, the spirillum of
cholera, yet not the cause of any particular diseased
condition.