THE IDENTIFICATION ОЕ THE MOST CHARACTER- 
ISTIC SALIVARY ORGANISM, AND ITS RELATION 
TO THE POLLUTION OF AIR! 
AUGUST G. NOLTE 
INTRODUCTION 
Bacteriologists and sanitary engineers have, within the last 
score of years, given much attention to the detection of excre- 
mental pollution in water. They have shown that by making 
it possible to recognize certain characteristic accompanying 
organisms, bacteriological methods are capable of revealing 
this kind of pollution even when it exists to such a small degree 
as to be beyond the range of chemical detection. Small as 
these quantities of contaminating substances may seem, they 
may nevertheless endanger the health of a whole community 
by exposing it to possible pathogenic organisms derived from 
the excreta of a diseased host. 
It is not merely by the aggregate bacterial yield that the 
potability of a water in its relationship to disease is judged, 
but more specifically by the species of bacteria present, and 
their relative abundance. The micro-organisms which serve 
as an index of pollution, and for which special quantitative 
examination is made, are the members of the colon group. 
These, from their constant presence and relative abundance, 
are characteristic of material of excremental origin. Their 
presence in water in sufficient quantity indicates pollution, 
and their relative abundance serves as an index to the extent 
of the latter. 
Bacteriological technique has not as yet been applied to 
the same extent in the detection of pollution in air. Chemistry 
has, up to the present time, been of more practical value here. 
1 An investigation carried out at the Missouri Botanical Garden in the Graduate 
Laboratory of the Henry Shaw School of Botany of Washington University, and 
submitted as a thesis in partial fulfillment of the requirements for the degree of 
master of arts in the Henry Shaw School of Botany of Washington University. 
ANN. Мо. Вот. GARD., Vor. 1, 1914 (47) 
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