| - |
| B. dysenteriae (Flexner)| O | O | O | O | + | O |+/-| + | - |
| B. faecalis alkaligines | O | O | O | O | O | O | - | - | - |
| | | | | | | | | | |
+-------------------------+-----+-----+-----+-----+-----+-----+---+-----+-----+
| Table Notes: | |(D)| (E) |
+-------------------------+-----------------------------------+---+-----------+

Table Notes:

(A) * Liquefies gelatine.

(B) + = motile. - = non-motile.

(C) + = acid or gas production. +/- = slight acid production. O = no
change.

(D) + = indol production. +/- = slight indol production. - = no indol
formed.

(E) + = acid production. - = alkali production. O = no change in
reaction. C = clot.

21. Determine the pathogenicity for mice (subcutaneous inoculation) and
rabbits (intravenous inoculation) of the streptococci isolated.

On the facing insert page is reproduced a blank from the author's
Laboratory Water Analysis Book, by means of which an exact record can be
kept, with a minimum of labour, of every sample examined.

B. ~Concentration Method.~

The remaining organisms referred to on page 426 are more conveniently
sought for by the concentration method.

_Collection of the Sample._--The quantity of water required for this
method of examination is about 2000 c.c., and the vessel usually chosen
for its reception is an ordinary blue glass Winchester quart bottle,
sterilised in the hot-air oven, and over this a paper or parchment cap
fastened with string. The bottle may be packed in a wooden box or in an
ordinary wicker case. The method of collecting the sample is identical
with that described under the heading of Quantitative Examination; there
is, however, not the same imperative necessity to pack the sample in ice
for transmission to the laboratory.

_Apparatus required_:

Sterile Chamberland or Doulton "white" porcelain open mouth
filter candle, fitted with rubber washer.

Rubber cork to fit mouth of the filter candle, perforated
with one hole.

Kitasato serum flask, 2500 c.c. capacity.

Geryk air pump or water force pump.

Wulff's bottle, fitted as wash-bottle, and containing
sulphuric acid (to act as a safety valve between filter and
pump).

Pressure tubing, clamps, pinch-cock.

Retort stand, with ring and clamp.

Rubber cor