80 BACTERIA 
of the plants at Little Falls, N.J., and Albany, N. Y. Diagrams indicate 
the results of water purification as measured in the saving of human life. 
Finally a series of five large relief maps show the growth and develop- 
ment of the water supply of New York City. 
Following the water-supply exhibit is a series of models illustrating 
ae the dangers from improper disposal of the liquid wastes 
City Wastes of the city and how they may be avoided. Actual points 
of danger in the neighborhood of New York are shown 
where polluted harbor waters, bathing-places, and shellfish beds consti- 
tute a menace to health. Modern methods for the treatment of sew- 
age on scientific lines are illustrated by a series of models of screens, 
sedimentation tanks, and filter beds of various types. 
The cases near the window are devoted to the group of Bacteria, espe- 
cially in their relation to human life. Glass models show 
the various shapes and relative sizes of these minute forms, 
and in particular of the principal types which cause disease. In anearby 
case are displayed actual colonies of a number of species of bacteria, 
including some which produce disease and others which are beneficial 
to man by their effect upon soil fertility or from the facé that they may 
be utilized in the production of substances useful as foods or in the arts. 
A group of transparencies at the window shows some of the more im- 
portant disease bacteria as they appear under the microscope. 
Bacteria 
Another series of exhibits deals with the transmission of disease 
by insects, notably by the fly and flea and by the mosquito. The 
most striking features are greatly enlarged models of the 
Insects fly, the flea, and the louse. These, the finest models of 
and : 
Disease the kind ever made, were prepared by the late Ignaz 
Matausch from his original studies, and required several 
years of constant, exacting labor. 
The egg, larva and pupa of the fly, and the eggs of the louse are 
also shown. 
Models in the wall case deal with the life history of the fly, showing 
its various stages in their natural size and actual habitat, and illustrate 
the large numbers of flies which may breed in a single pound of manure 
and the enormous progeny which may spring from a single pair and their 
descendants during the breeding season. 
The deadly work of the fly in carrying typhoid fever is illustrated by 
graphic presentations of typhoid statistics of the Spanish-American 
War and of the relation between flies and “‘summer disease”’ of children, 
as worked out by the Association for Improving the Condition of the 
Poor in New York City. 
