July 2, 1894/j THE TROPICAL AGRICULTURIST. 
9 
CEYLON MANUAL OF CHEMI- 
CAL ANALYSES. 
A HANDBOOK OF ANALYSES CONNECTED WITH 
THE INDUSTRIES AND PUBLIC HEALTH OF 
CEYLON FOR PLANTERS, COMMERCIAL MEN, 
AGRICULTURAL STUDENTS, AND MEMBERS OF 
LOCAL BOARDS. 
By M. COCHRAN, m.a., f.c.s., 
( Continued from page 802.,) 
CHAPTER XIII. 
DISINFECTANTS, ANTISEPTICS AND 
DEODORIZERS. 
Definitions of disinfectants, antiseptics 
and deodorizers— experiments to deter- 
mine the ' amounts of antiseptic sub- 
stances required to prevent and to check 
putrefaction- chlorine and chlorinated 
lime — permanganate and manganate of 
potassium— hartman's crimson salt— phe- 
nols— carbolic acid — dr. calvert's experi- 
ments — lysol— chief antiseptics used as 
food preservatives -chief deodorizers- 
directions for the use of carbolic acid 
crystals, &c.— jeyes' disinfectants. 
Disinfectants, A jitiseptics and Deodorizers- 
Disinfectants are bodies which destroy disease 
germs. Disinfectants are also antiseptics. Anti- 
septics are bodies which prevent purtrefaction, 
but do not necessarily destroy living germs. 
Antiseptics therefore may or may not be 
disinfectants. Deodorizers absorb or destroy 
unpleasant odours ; but dp not necessarily act 
either as antiseptics or disinfectants. 
In Thorpe's " Dictionary of Applied Chemistry," 
in the article on Disinfectants by A. H. Allen, to 
which I am indebted for a number of the following 
facts and figures, the results of experiments to 
determine the amounts of antiseptics required 
to prevent and check putrefaction in a liquid of 
known composition are given. Pasteur's liquid 
was used, consisting of 10 grams common sugar, 
1 gram tartrate of ammonium and half a gram 
of phosphate of potassium in 100 cubic Centimeters 
of distilled water. A number of tubes were filled 
with this solution together with different amounts 
of the antiseptic, and a few drops of a decom- 
posing infusion of tobacco. The following table 
2 
shews the smallest amounts of antiseptics which 
prevent the development of bacteria : — 
1 part in 
Corrosive sublimate ... ... 20,000 
Thymol ... ... ... 9 000 
Sodium benzoate ... ... 2 000 
Creosote .. ... ... 2'o00 
Benzoic acid ... ... 1000 
Methyl salicylic acid ... '666 
Eucalyptol ' ... ... 666 
Sodium salicylate ... ... 250 
Carbolic acid ... 200 
Quinine ... ... ... 200 
Sulphuric acid ... ■ ... 151 
Boric acid... ... ... 133 
Cupric sulphate ... 133 
Hydrochloric acid ... ... 75 
Zinc sulphate ... ... 50 
Alcohol ... ... ... 50 
The smallest amounts which would arrest 
putrefaction and render the bacteria incapable of 
further development when removed to fresh 
Pasteur's solution, were found to be as follows :— 
1 part in 
Chlorine ... 
Iodine 
Bromine 
Sulphurous acid 
Salicylic acid 
Benzoic acid 
Methyl salicylic acid 
Sulphuric acid 
Creosote ... 
Carbolic acid 
Alcohol 
As a disinfectant or 
antiseptic, 
25.000 
5,000 
3,333 
GGti 
312 
250 
200 
161 
100 
25 
4-5 
chlorine is 
mostly employed in the well-known form of 
chlorinated lime, or bleaching powder, which is 
often represented by the chemical formula 
Ca (OCl) 2 + CaCl 2 , but better represented by 
Ca < OC1) CI, seeing that in good bleaching powder 
nearly all the chlorine is available, a very small 
proportion being present as chloride. Thus a 
good bleaching powder has the following composi- 
tion :— 0 1 
Analysis bi/ J. Pattinson. 
Available chlorine 
Chlorine as chloride 
Chlorine as chlorate 
Lime 
Magnesia ... 
Peroxide of iron 
Alumina 
Oxide of manganese 
Carbonic acid 
Siliceous matter 
Water and loss 
Total chlorine 
Bleaching powdtr deteriorates by 
per cent. 
. 37-00 
•35 
•25 
. 44-49 
•40 
05 
43 
trace 
•18 
•40 
. 16-45 
100-00 
. 37-60 
---—«, j, - — » „j seeping even 
in closed vessels, part of the available chlorine 
passing into chloride which is not an available 
form. 
The properties of lime as a disinfecting agent 
are universally recognised. Its purity depends 
on the purity of the limestone or natural carbon- 
ate of lime, from which it has been prepared, 
and on the thoroughness of the heating in the 
kiln. 
The alkaline permanganates and manganates 
have for many years been in favour as disinfect- 
ants. Condy's crimson and green disinfecting 
fluids are well known; the colour of the former 
