DISCUSSION 
Price: Can I ask as a layman if these biochemically natural 
foods might have unfortunate side effects, like the artificial 
additives? Have any screening tests been made? 
Pirie: No. One eats quite a lot of leafage in various forms 
already, without, so far as I know, any side effects, nor are they 
to be expected. But there are goitrogens in cabbage. 
Lederberg: I think you should be quite cautious about 
exposing people to a great deal of jute pulp until tests have been 
carried out. 
Price: In Malaya the Chinese girls eat certain pineapple 
shoots as a birth control measure. 
Pirie: Are they effective? 
Price: ‘They are said to be! 
Wright: ‘There are tremendous potentialities in the oceans 
which we have not mentioned so far. Only about one-tenth of 
the world’s animal protein and one-hundredth of the world’s 
total food supplies are derived from this source. There is no 
doubt that the potentialities for catching fish, and for fish 
culture inland, in tanks, are both enormous and economic. The 
latter is already being developed on a very considerable scale. 
Hoagland: ‘There is one source that has not been tapped in 
the Antarctic, namely, squill, the shrimps that form the favourite 
food of the baleen whales. They are said to offer a yield of 
animal protein per unit area of ocean something like several 
times the yield of the best land grazing areas. They are exceed- 
ingly plentiful but as far as I know no one has made any serious 
attempt to harvest them. 
Clark: An attempt was once made in Australia. The dis- 
tances are such that it was found uneconomic, at the present 
price of proteins, but when they go up this may change. The 
FAO report on Fish Farming and Inland Fishery Management (1954) 
and some work from Nigeria (see Pedler, Economic Geography 
of West Africa) suggest a gross yield from fish in ponds up to 2 
tons per hectare per year. The Danish oceanographic research 
ship found a rate of photosynthesis in some parts of the oceans 
of about 5 grams per square metre per day, which is comparable 
with ordinary farm land. This is in regions where the upwelling 
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