ntericus fuscus.

XIV. _Acid fast group._

Bacillus tuberculosis (human).
" " (bovine).
" " (avian).
" " (fish).
to contrast with
Bacillus phlei (Timothy grass bacillus).
Butter bacillus of Rabinowitch.

XV. _Plague group._

Bacillus pestis.
B. septicaemiae haemorrhagicae.
B. suipestifer.

XVI. _Influenzae group._

B. influenzae.
Bacillus aegypticus (Koch-Weeks).
Bacillus pertussis.

XVII. _Miscellaneous._

Bacillus leprae.
Bacillus mallei.
Micrococcus melitensis.

XVIII. _Streptothrix group._

Streptothrix actinomycotica.
Streptothrix madurae.
to contrast with
Cladothrix nivea.

XIX. _Tetanus group._

Bacillus tetani.
Bacillus oedematis maligni.
Bacillus chauvei (symptomatic anthrax).

XX. _Enteritidis sporogenes group._

Bacillus enteritidis sporogenes.
B. botulinus.
B. butyricus.
B. cadaveris.

FOOTNOTES:

[15] See note on Vivisection License, page 334.

XXI. BACTERIOLOGICAL ANALYSES.

Each bacteriological or bacterioscopical analysis of air, earth, sewage,
various food-stuffs, etc., includes, as a general rule, two distinct
investigations yielding results of very unequal value:

1. Quantitative.
2. Qualitative.

The first is purely quantitative and as such is of minor importance as
it aims simply at enumerating (approximately) the total number of
bacteria present in any given unit of volume irrespective of the nature
and character of individual organisms.

The second and more important is both qualitative and quantitative in
character since it seeks to accurately identify such pathogenic bacteria
as may be present while, incidentally, the methods advocated are
calculated to indicate, with a fair degree of accuracy, the numerical
frequency of such bacteria, in the sample under examination.

The general principles underlying the bacteriological analyses of water,
sewage, air and dust, soil, milk, ice cream, meat, and other tinned
stuffs, as exemplified by the methods used by the author, are indicated
in the following pages, together with the methods of testing filters and
chemical germicides; and the technique there set out will be found to be
capable of expansion and adaptation to any circumstance or set of
circumstances which may confront the student.

~Controls.~--The necessity for the exis