SANITARY INSPECTION 269 
MacNutt (1910) were studying the effect of water treatment on disease 
they gave the name “ Mills-Reincke Phenomenon ”’ to this observation. 
They stated that infant mortality was closely related to water supply. 
Also a decrease in tuberculosis was reported for an umprovement in the 
water supply. Hazen (1910) reported somewhat the same fact that 
‘‘ where one death from typhoid fever has been avoided by the use of a 
pure water, a certain number of deaths, probably two or three, from 
other causes have been avoided.” This has become known as the 
‘‘Hazen Theorem.” These statements have not been entirely borne 
out by a more careful study. Fink (1916) has pointed out that an error 
enters in comparing the total mortality with the typhoid death rate. He 
states that there are two factors which may cause a variation in the ratio 
between the total and the typhoid fever death rate. , ‘‘ One is the rate 
at which the general mortality is being lowered and the other is the 
height of the typhoid fever death rate before filtration and the propor- 
tion due to water-borne infection.” 
The spread of typhoid fever by impure water has been so prevalent 
in the past that the disease is often referred to as a water-borne disease. 
Many data are on record to show a decided decrease in the typhoid fever 
death rate when an improved water supply has been made available to a 
community. Fig. 58 prepared by McLaughlin shows this reduction for 
Pittsburg. 
Sources of Water Supply. The sources of water supply may be 
classified as follows: 
A. Surface supplies 
(a) Lakes 
(b) Rivers 
(c) Upland gathering grounds 
(2d) Impounding reservoirs 
B. Ground water supplies 
(a) Shallow walls 
(b) Deep wells 
1. Artesian 
2. Bored 
3. Dniled 
(c) Springs 
Sanitary Inspection. Too little attention is given to sanitary in- 
spection in water analysis’ The analyst is quite inclined to regard his 
results as sufficient data for passing judgment on a water supply. 
