SANITARY PRIVY. on 
of heat. Any other method, such as burial or any practicable treat- 
ment with chemical disinfectants (lime, etc.), although lessening the 
danger to some extent, still carries with it risks involving human life. 
If the wet method (p. 16) be used in the style of privy shown in 
figures 6 and 7, the excreta had best be heated to 212° F., after which 
the material may safely be used as fertilizer. A second method is to 
permit the filth to ferment in water in covered tubs or barrels for not 
less than a week after removal from the privy; then pour in a disin- 
fectant (such as chloride of lime, one-fourth pound to the gallon of 
excreta) ; the material should then be buried. This second method 
greatly reduces but does not entirely remove the danger of the spread 
of disease. 
fluent (overflow) from the L. R. S. privy—F rom what has been 
said above, it is clear that the proper disposal of night soil always 
involves some labor and trouble, but it is important constantly to 
hold in mind the truth that the results obtained, in better health, 
smaller doctors’ bills, and the saving of human life, more than justify 
the efforts expended. 
The L. R. S. privy reduces the volume of the excreta and converts 
the material into an easily manageable fluid, so that the disposal of 
night soil from this type of privy is much simplified. The methods 
of disposal which come into consideration are the following: 
(1) Heat: If a suitable (metallic) vessel is provided to receive the 
effluent, a fire may be built under the vessel and the effluent heated 
to 212° F. Or if a wooden or concrete effluent tank is used, the 
effluent may be transferred to some other vessc' for heating. 
After such treatment the fluid may be sateiy «ced for fertilizer 
under any conditions. 
Heat disinfection is the only measure which can to- -day be recom- 
mended unreservedly. 
(2) Burial: Burial will unquestionably decrease the danger c* 
spreading infection, but in the present state of knowledge this method 
of disposal can not be relied upon as safe. If burial of the effluent 
is practiced, the fluid should be disposed of not less than 300 feet 
from and downhill from any neighboring water supply and not less 
than 2 feet underground, and then only provided the soil itself is a 
good filter. Burial in a limestone region may contaminate water 
supplies miles away. 
(3) Chemical disinfection: Chemical disinfectants, such as chlo- 
rinated lime and certain coal-tar derivatives, have the great advantage 
of cheapness and can be relied upon to destroy the disease-causing 
bacteria in the night soil. The knowledge regarding the action of 
chemical disinfectants upon the eggs and spores of the various animal 
parasites is at present very rudimentary, but, so far as results are 
known, their practicable use does not seem to be so efficient in the 
463 
