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26
itinerary. Many of the largest sewage treatment works were visited as were also
research institutions, and much extremely useful information was obtained which
will be valuable both from the cost and efficiency aspects in the detailed planning of
the new works. The preconceived ideas on the main design were however not
fundamentally altered.
Public Health
Regular chemical analyses and bacteriological examinations were made of the
drinking waters derived from private wells at various Council premises and at hospitals
both before and, by arrangement with the Committees concerned, after the
handing over to the Regional Boards. All these water supplies are chlorinated before
use and the dosage was periodically checked. Assays were made by various methods
of the polluting matter (total deposit, tarry matter, sulphur gases, etc.) in the air in
various parts of London and also for comparison at places outside the County. This
work was done in conjunction with a scheme sponsored by the Department of Scientific
and Industrial Research, and the Chemist-in-Chief continued to be a member
of the Atmospheric Pollution Research Committee of this department. The air
in the Council's vehicular tunnels was regularly examined in order to ensure that
the carbon monoxide content did not exceed the safety limit; in view of the continued
use of petrol containing lead compounds the lead content of the air was also
checked occasionally and was found to be safe. The cause of onset of cases of
dermatitis was examined in some instances and the use of " barrier creams " was
considered from the theoretical aspect of their formulae and protective action. In
one instance the possible causative agents were narrowed down to typewriter ribbons
and ink with which the hands were liable to come into contact. The ink was found
to contain arsenic and a doubtful type of dye from the dermatitic aspect. The
question of fluorine and teeth was kept under review, for an excessive ingestion of
this element causes mottled teeth whereas a deficiency is now considered to assist
the onset of dental caries. Water supply is an important source of fluorine and
largely on the basis of work done in America, it has been postulated that a supply
containing about 1 part per million is the optimum; London water derived from the
river Thames and Kent wells contains less than 0.2 parts per million though that
from some wells north of London contains about 0.6 parts per million.
School and
other meals
The work done in co-operation with the Restaurants and Catering Department
was continued and many meals were analysed as to their nutritional value by the
determination of their fat, protein, carbohydrate and mineral contents, and of their
calorific value. Attention was also given to the ascorbic acid (Vitamin C) content.
Having regard to the continued difficulty in the supply position the results showed a
reasonably good approach to the targets aimed at for the nutritional factors for the
various age groups concerned. Some "sandwich meals" were also examined, these
being a useful occasional alternative to the full meals: these meals were of a reasonably
good standard nutritionally. Plastic plates suggested for use in lieu of china
ones in short supply were examined and their defects were pointed out.
Public
Control
Samples taken under the Fertilisers and Feeding Stuffs Act, 1926 (under which
the Chemist-in-Chief is the Official Agricultural Analyst for the County) were examined
as to whether they complied with the statutory statement of ingredients which is
required to be given with every sale and also (in the case of feeding stuffs) as to their
freedom from deleterious substances. A considerable number were reported upon
adversely ; for example, samples of both rice meal and barley meal were adulterated
with considerable proportions of chalk. Many samples were also examined under the
Petroleum (Consolidation) Act, 1928, the London Building Act, (1930) and the
Explosive Acts. Those under the last-mentioned were mainly of indoor fireworks ;
they were mostly of the "sparkler" type, and were found to be made of mixtures of
barium nitrate, iron filings, aluminium powder and gum and to be scheduled in the
list of Authorised Explosives, Class 7, Division 2. In view of the possible imposition
of regulations, the atmosphere in many garages was examined to test the ventilation