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to point out, that it seems probable that there is some difference in the power of
resistance of the various members of this group, and that one or the other may
subsequently be demonstrated to be rather susceptible.
Bacillus No . 9.—This organism very much resembles acidi lactici, with the
exception that it gives Voges' and Proskauer's reaction. It has only been isolated once
from fœ ces, namely, from cowdung. In the month of February it was found to be
very common in the water-supplies of Vellore and Gudiyáttam and rarer in a few
others. The prevalence of this organism in several places tends to show that it is a
separate species, and, that it is not an odd specimen of acidi lactici, which (according
to some authorities) has acquired. the power of giving Voges and Froskauer's
reaction. Nothing can be stated. as regards its power of resisting the action of
sunlight.
Bacillus No . 10.—This is one of the rare organisms that appeared in
September and October about the bursting of the monsoon. It has been found in
human fœeces and cowdung, and in water-supplies at that time, but never before or
since. Nothing whatever is known about its natural characteristics, except the fact
common to all these bacilli, that they disappear very rapidly from all supplies.
Bacillus Colic Gommunis( N o
. 3 4 )
a n d B a c i l l u s S c h œ f f e r i N o s.
3 5
a n d
3 6 . — T h i s
little group of organisms (the difference between the several members being shown only
in motility and indol production) is the most important of all, from the point of view of
a sanitarian. As is well known, the organism is found. in the fœces of all animals
our figures show that it is commoner in the dejecta of man than in those of cattle.
It is found in water-supplies from rivers, lakes and wells equally on certain occasions.
It has been. found by us to live in dry ground for at least 97 days, but it was
not found in the samples of highly polluted earth examined by us. Several points
about the existence of this organism in soil have been discussed in Chapter VI. It
may live in the lower damp layers of a porous soil, but the subject of the viability
of this organism in earth, is one that requires further work. The micro-organism
is the typical example of the susceptible group. Results recorded. in Chapters VIII,
IX and X all decidedly support this.
Bacillus No . 33.—This bacillus is similar to colic communes except that it
ferments adonit. It is a moderately rare organism, appears to be more common in
human fœces than in cowdung. It is occasionally found in water samples. For a
long time we looked upon it as being confined to human fœces only, but extended work
proved. this to be incorrect. It possesses the power of resisting sunlight to a moderate
degree and belongs to class II. Attention is drawn to experiment No. 1 and others in
Chapter VIII, showing that this organism appeared after colic communis had entirely
disappeared, and persisted for some time. It cannot, therefore, be looked upon as such
a good. indication of recent pollution as colic communis.
Bacillus No . 38.—This is a rare organism about which we know very little. It
has always been found. in water. It gives the same fermenting reactions as No. 33 ;
but the Voges and Proskauer reaction is positive. Whether it ought to be placed in
the 1st, 2nd or 3rd class we are unable to state.
Bacillus No. 37.—This is a very rare organism, it has never been isolated from
fœeces but has occasionally been found in water samples. Nothing further can be
stated as regards its other characteristics.
Bacillus No . 39.—Little is known concerning this organism. The remarks made
for No. 10 applies to this bacillus.
Before passing to the next group, it is very interesting to note, that, even in such
a small list of organisms as that in MacConkey's group 2, there is at least one (and
probably two) which show a pronounced difference in power of resistance to
the action of sunlight, thereby confirming the statement made in Chapter III, that
it is not legitimate to conclude that all organisms giving the same results in a few
fermentation reactions, are equally indicative of undesirable excretal pollution.
Oxytocus Ferniciosus No . 65.—This is a perfectly well-known organism. It has
never been isolated by us from the fœces of either man or cattle, but it must exist in the
dejecta of cattle at any rate. It has been found in water-supplies in October (vide
Chapter V). The same remarks, made regarding No. 10, apply to this organism also.
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