J 
4 
ferrous sulphate^ should be brought into direct contact with the excreta. In practice, 
a proportion of five parts of the iron salt in each hundred of the total contents of the 
latrine vault should be considered as essential to efficiency. In the French army 
ferrous sulphate is much used for the disinfection of latrines in a 10 per cent solution. 
It is officially laid down that at least 250 c. c. of such a solution should be used per 
day for each person using the latrine. 
Sternberg found that a solution of 20 per cent failed to destroy 
micrococci and putrefactive bacteria (1883). Later he found that 10 
per cent failed to kill pus cocci, but was fatal to micrococcus tetrag- 
euous — two hours’ exposure. He also found that 1: 200 prevented the 
development of micrococci and of putrefactive bacteria in bouillon 
placed in the incubator for forty-eight hours. 
Jager ^ found that a solution of 1: 3 destroyed the infective virulence 
c/' 
of some pathogenic organisms (fowl cholera, rothlauf, glanders), as 
tested by injection into mice, but failed to kill anthrax spores and 
tubercle bacilli. 
Leitz® found that a 5 per cent solution required three days’ exposure 
for the destruction of the typhoid bacillus. 
In a series of experiments bearing upon the disinfection of feces, 
Foote mixed decomposing urine with feces, 1 part feces to two-thirds 
of its bulk of urine. Five hundred c. c. of the disinfectant mixture 
(ferrous sulphate 1 xviii, water 1 gallon) was added to 250 c. c. of 
the feces-urine mixture and the two thoroughly mixed. Inoculations 
of one platinum loopful were made from the mixture into gelatin and 
bouillon after one hour, four hours, and fort}"-eight hours of action. 
The sulphate of iron solution had little if any effect. Even after 
forty-eight hours’ action the colonies upon the gelatin plates were 
innumerable and a profuse growth appeared in the bouillon tubes. 
In order to ascertain the antiseptic and disinfectant value of ferrous 
sulphate a number of experiments were carried out with the results 
shown in the following tables: 
ANTISEPTIC POWER OF FERROUS SULPHATE. 
Table I. 
Bouillon with the addition of ferrous sulphate in various j^ercentages contaminated 
by the addition of a small quantity of garden earth. Kept at room temperature. 
Proportion of fer- 
rous sulphate. 
First day. 
Second day. 
Third day. 
Tenth day. 
Twenty-first 
day. 
1:200 
Vervfoul odor 
Foul odor. 
Xo odor. 
Do. 
Do. 
Do. 
1 : 150 
do 
1-100 
do 
1 : 50 
Foul odor 
Very foul odor 
Xo odor 
1:40 
Xo odor 
Foul odor 
1 : 30 
do 
do 
do 
1 ; 25 
do 
Xo odor 
Faint odor 
Xo odor 
1 : 20 
do 
do 
do 
1 : 15 
do 
do 
do 
1.10 
do 
do .r 
do 
do 
1.5 
do 
do 
do 
« Cited by Sternberg. 
