APPENDIX V 
311 
the effluent may be transferred to some other vessel 
for boiling. 
After boiling, the fluid may be safely used for fer¬ 
tilizer under any conditions. 
Heat disinfection is the only measure which can to¬ 
day be recommended unreservedly. 
(2) Burial: Burial will unquestionably decrease the 
dangers of spreading infection, but in the present state 
of our knowledge this method ’of disposal cannot be 
relied upon as safe. If burial of the effluent is prac¬ 
tised, the fluid should be disposed of not less than 300 
feet from and downhill from any neighboring water 
supply and not less than two feet underground, and 
then only provided the soil itself is a good filter. Bur¬ 
ial in a limestone region may contaminate water sup¬ 
plies miles away. 
(3) Chemical disinfection: Chemical disinfectants, 
such as chlorinated lime and certain coal-tar deriva¬ 
tives, have the great advantage of cheapness and can 
be relied upon to destroy pathogenic bacteria. Our 
knowledge regarding the action of chemical disinfec¬ 
tants 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 destruction of the zooparasitic 
as of the bacterial infectious organisms. Therefore, 
pending further investigations, the use of chemically 
treated excrement as fertilizer should not be regarded 
as unqualifiedly safe. 
(4) Chemical disinfection with subsequent burial: 
