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1906]
192
DISINFECTION.
Disinfectants.—For the first time in buying carbolic disinfectants,
the Public Health Committee resolved that they should be tendered for
according to their germicidal or bacteriological value, so that so far as possible
those with high germicidal properties, and consequently costing more money,
might be placed on an equal footing with those whose power was not so great.
This method of tendering has come about owing to the standardisation of
disinfectants by a process invented by Messrs. Rideal and Walker, and is
known as the " Rideal Walker Method."
The means of arriving at the relative cost of each is simplicity itself and
is ascertained by dividing the co-efficient of efficiency, which interpreted
means the number of times the disinfectant is stronger than pure carbolic
acid when acting on a pure culture of B. Typhosus, into the price of
the disinfectant. By this method the cost per gallon per co-efficient is
ascertained. For example, if a sample with a carbolic acid co-efficient of n is
quoted at 4s. per gallon, its cost per co-efficient would work out at 4^d., and
similarly a disinfectant whose carbolic acid co-efficient was 4*5 and price gd.
per gallon, would work out at 2d. per co-efficient. Thus in purchasing, the
Sanitary Authority is enabled to procure an article whose exact germicidal
value as compared with pure carbolic acid is known.
So far the method has answered satisfactorily, but in future it would be
well for the Council to invite tenders for disinfectants on the basis of a fixed
carbolic acid co-efficient. In this way all manufacturers of disinfectants would
be equally enabled to tender on an equality, while the Sanitary Authority would
get the exact article it required and it would not be necessary for them to
reduce the strength of the disinfectant to that at which they would use or
distribute it.
The disinfection of rooms, as well as their cleansing and stripping,
of schools, and of clothing and bedding, are important features of the work of
the Public Health Department. During the last few years also, owing to the
passing of the provisions dealing with the disinfection of the premises and
clothing of verminous persons, work of this character has fallen on the department,
and consequently its duties have been slightly increased, but fortunately
nothing more than it has been able to deal with.
Prior to 1895, when the Disinfecting Station was erected, the disinfection
of clothing, bedding and articles that had been exposed to an infection were
sterilized (?) by private contractors, and in the year ending 1895 (March), £378
were paid for that purpose. Since that date this work has been done by the