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Different teats tested when new and at a similar pressure showed a wide variation in
flow rate; boiling tended to reduce the rate of flow. The presence of rims and flanges
was found to be a hindrance to cleaning.
The effect of different methods of sterilisation in the useful life of a teat was also
studied. Teats placed in a covered jar on a rack in a domestic pressure cooker showed the
least deterioration but some teats developed a rather unpleasant smell. The use of
hypochlorite solution for sterilisation caused less damage than did boiling.
For the purpose of contract the quality and useful life have to be considered in relation
to the price.
(c) Sterility tests were carried out on the components of maternity sets with satisfactory
results, but sheets of various types of cellophane, which were being considered as
temporary covers for burned surfaces, were found to carry a few aerobic organisms on
receipt from the makers. They were not, however, heavily contaminated.
Industrial safety and hygiene
Advice was given on several matters coming under this general heading. Amongst these
may be mentioned the following particular cases:
Crayons and pencils—The observation, published last year, that crayons and grease
pencils sometimes included poisonous ingredients roused considerable interest amongst
other authorities concerned with the health of school children and the supply of educational
equipment. Enquiries were also received from the makers of certain crayons and pencils
as to whether wood-cased pencils were under discussion as well as unprotected crayons.
It is now apparent that instances have occurred where both coloured and black lead
pencils in wooden cases have been lacquered externally with paints containing large
proportions of lead chromate. As there is a common tendency for children to suck or chew
their pencils there can be little doubt that in these cases pencils could be responsible for
some part of the intake of lead which may ultimately develop into symptoms of lead
poisoning. As an indication of the seriousness of this matter it may be mentioned that the
lacquer on a single pencil has been found to contain up to 250 mgm. of lead. There is of
course no need to incorporate any poisonous ingredient in these lacquers and no difficulty
has been found in securing innocuous supplies by asking for them specifically. For this
reason consideration has been given to formulating tentative limits for the amounts of
certain poisons that would be permissible, and it is thought that a limit of 10 mgm. of
metallic lead in the lacquer of a pencil would be reasonable. This would be in close
alignment with practice in the United States of America where there is prohibition of all
paints containing more than one per cent of lead in the 'ready for use' condition. A
similar limit would be desirable for soluble chromium, thus allowing the use of insoluble
chromic oxide; and also for soluble barium (allowing insoluble barium sulphate as
extender). It is further suggested that the lacquer of a pencil should not contain acidsoluble
antimony, arsenic, soluble cadmium, or selenium in excess of 10 mgm. These
limits may be reduced if more than one poisonous constituent is present.
Disposal of dangerous chemicals—Surplus chemicals including cyanide from schools and
colleges which had undergone reorganisation were collected for safe disposal or other use.
Considerable quantities of dangerous chemicals were removed from a disused pharmaceutical
chemical works. At another works a large quantity of cyanide in solution was
destroyed by careful oxidation with bleaching powder.
Dangerous chemicals must not be put into the sewers and in some cases burning is not a
safe means of disposal. Disposal of unwanted chemicals cannot be undertaken by refuse
collection services of local authorities and it would appear that a special service is required.
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