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212°F. or more ; and (3) that articles suitable for disinfection by  moist
heat shall not be spoiled during the process.
4. Special apparatus * should be available at all ports and in large
cities. Efficient disinfectors can some times be extemporised, especially
on lines of Railway where steam from locomotives can be provided, but
it must be ascertained that all such contrivances fulfil the three con-
ditions mentioned above.
Every disinfector must be worked by a trustworthy man who under-
stands it, the workman having been instructed in the use of the parti-
cular apparatus by a Medical officer who has ascertained experimentally
how to get effective work from it, and has laid down definite rules † for
the guidance of the operator.
5.  But expensive disinfectors are not always available,  and a boiler
of some kind must often be used.    Even in such cases, rules for the
guidance of the men using the boiler must be prescribed.    It is less
difficult to secure a high and uniform temperature when the vessel used
can be covered, and it must not be forgotten that the temperature of the
water will be lowered whenever a fresh article is plunged  into it.    It is
essential, then, that arrangements should be made to secure that every
article to be disinfected by boiling should be completely immersed, and
exposed to the boiling temperature for not less than ten minutes.
6.  Chemicals ‡ must be used when the employment of moist heat is
impossible ; and it is well to add that there is at any rate a theoretical
objection to the use of chemicals for the disinfection of organic  matter
such as clothing, because albuminous substances may combine with the
chemicals, and form a protecting envelope to the germs it is desired to
reach §.
7.  It is of the first importance that the chemicals should be sufficiently
pure to be effective, and although it is impossible here to discuss more
than two of the disinfectants in most general use,-perchloride of mer-
cury and carbolic acid-it may  be remarked that a sample of " crude
perchloride  of mercury " recently purchased in Calcutta contained no
perchloride at all, and that much of the commercial carbolic acid in
general use contains very little phenol and very much comparatively
inert tar oils.
* Note.-The Madras port has a disinfecting machine obtained from England. Tunga-
bhadra and Arkonam have apparatus designed by Mr. Moss, Public Works Department,
in consultation with the Sanitary Commissioner, Madras, while at Hospet disinfection
is carried out with a machine lent by the Southern Mahratta Railway.
† Note.-Rules for working efficiently the steam disinfecting machines are in the pos-
session of the officers in charge. Copies can be obtained on application to the Sanitary
Commissioner.
‡ Note.-The following remarks of M. Haffkine should be noted: "The general
tendency to seek protection, during epidemics, in bonfires, fumigation, gaseous disinfect-
ants, &c., is based upon a notion that infection exists in, and may be carried and com-
municated by, 'vicious air.' This notion is deprived of any experimental foundation
whatever ; on no occasion was there reason, in the least sufficient, to believe that the
air was the actual vehicle of contagion in any of the diseases which have been put into
the category of the so-called ' air-born diseases ;' and all investigations made up to the
present go to show that air is free from pathogenic microbes."- G.O., No. 1306-P., dated
11th October 1898
§ Note.-Hence the importance of using hydrochloric acid with the solution when
employing perchloride of mercury.