DISCUSSION 
for obtaining the juice and tried many different leaf species. 
Brock: Do you get rid of the chlorophyll that comes out in 
your juice? 
Pirie: It can easily be done by solvent extraction but why 
bother? It is quite harmless. 
We cook the curd by, for example, placing about 2 grams, 
mixed perhaps with a little mashed banana, in small patties, 
which are then fried. Three of these per day meet 10 per cent 
of a normal person’s protein requirement. They are eaten 
avidly by my staff—they sometimes manage to eat the lot 
before the visitors, for whom the cooking was being done, 
arrive. 
Crick: How many people would one of your presses supply, 
if it were running continuously ? 
Pirie: A machine fed with reasonably moist leaf containing 
20 per cent protein (on the dry matter) at one ton per hour 
for 8 hours on 300 days in the year, would provide about 10 per 
cent of the protein requirement of 30,000 people. 
Crick: So the capital cost per head is really quite small? 
Pirie: Yes, the capital cost of a big machine is about £2,500 
including the essential pumps, tanks, etc. 
Lederberg: What raw material is there that is suitable for 
this in relation to other food supplies? What increment of our 
total available food would this represent? 
Pine: We use ordinary agricultural crops because if I used 
anything else, I’d have to grow it myself. These are not, of 
course, the ideal plants to use; if one were using the process 
economically, one would use much leafier crops than these. 
Ideally one would use some waste product—sugar cane is 
attractive. I have made protein out of sugar cane: whether it 
would be economic I am uncertain; it is awfully tough stuff, 
and its protein content is low, so that you have to do a fair 
amount of work to get out the protein. Other plants that 
interest me are sweet potato, ramie, and jute because the leaves 
are by-products. 
Hoagland: Is there no interest on the part of the Indian or 
other governments in regions where there are food shortages, 
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