.\( 1)1 lin.\ h'l-LK'S ti) 



iiUMiacr to health. The inodci-ii methods tor the t I'cat iiiciit of s('\v:i<;(' on 

 scientific hues are iiiusti-ated hy a s(>ries of models of screens, sedimenta- 

 tion tanks and filti^- Uv(\>< of various types. 



The cases near tlie window are dc^'oted to the <!;i-()Ui) of P)actei-ia. 



especialU' in their relation to human life, (llass models 

 Bacteria , ^, " , \ \ ^- r i i ■ * 



show tlu^ various shajK^s and relative sizes ol these minute 



forms and in i)articular of tlu^ ])rinci])al tyi)es wliicli cause disease. In 



a nearby case are disi)lay(Hl actual colonies of a nunibor of species of 



bacteria includin<2; some wliich i)roduce disease and others which are 



beneficial to man by their effect upon soil fertility or the fact that they 



may be utilized in the production of substances useful as foods or in the 



arts. A group of transpariuicies at the window shows some of the more 



important disease^ bacteria as they appear under the microscope. 



Another series of exhibits deals with tlu^ transmission of disease by 



insects, notably l)y the fly and flea. The most striking 



feature of these is a model of the fiv, a little over a foot in 

 \ and 

 ^ Disease length, and having the bulk of 64,000 flies. This? 



the finest model of the kind ever made, was prepared by 

 Ignaz Matausch from his original studies, and required nearly a year of 

 constant, exacting labor. 



The deadly work of the fly in carrying typhoid fever is illustrated by 



a representation of two companies of soldiers, showing the 



^ , . , comparative mortality from flies and bullets during the 



- Ply Spanish-American war. One company confronted b}' a 



cannon, suffers the loss of one man w^ounded; another 

 facing a tube of typhoid germs — distributed by flies — has one dead and 

 thirteen in the hospital. 



Nearby are tw^o models showing unsanitar}- and sanitary conditions 

 on a small farm. In one, pools of stagnant ^vater and uncovered 

 manure heaps and general uncleanliness favor the breeding of mosquitoes 

 and flies, while the open doors and windows give theses insects free 

 access to the house. In the other, the swampy land is drained 

 and cultivated, the Avindows screened, the shallow dug w^ell replaced 

 by a driven wtII; the conditions are sanitary and health and prosperity 

 replace sickness and poverty. 



The manner in which bubonic plague is disseminat- 

 The Flea ^^j jg show^n by a copy of a corner of a house in 



p, San Francisco infested by rats, which carry the fleas, 



that hold the germs that introduced into the blood by 

 the bite of an insect give rise to bubonic plague, the black death 

 of the Middle Ages. 



