MONDAY. (Week 1, London to Nairobi). Heathrow departure for Nairobi - a conference trip to Sri Lanka has subtly expanded to a five-week world tour. First stop is the Kenya Forestry Research Institute, prospective partners on forthcoming four-year research project funded by the European Union under its "Science and Technology for Development" programme to improve treatment of surface waters destined for drinking and waste-waters for agricultural reuse. The aim is to replace the proprietary chemical coagulants with the crushed seed powder of moringa trees.

TUESDAY. (Week 1, Lake Baringo, Kenya). We set off for a 16-hour field trip beyond Lake Baringo to see moringa trees. At noon, it is 42 degrees Celsius in the shade (not that there is any). Stop briefly on the Equator to select, tether and order lunch. After a breathtaking circuit of Lake Naivasha by dirt track we return to the Equatorial Cafe for an excellent meal of roast goat, boiled goat and goat soup. Surviving relatives gratefully devour bones and scraps.

Moringa trees are cultivated on the hot, coastal plain and the green, immature seedpods are harvested for export to Europe. They are highly prized as a vegetable by Indians around the world.

WEDNESDAY. (Week 2, Thyolo, Malawi). Join colleagues Victoria Travis and John Sutherland who are midway through a six-week field study in southern Malawi. They are testing an innovative water filtration technique - coagulant seed solution is added just before the river water enters the sand filter. Coagulation, flocculation and deposition occur entirely in the sandbed. The results on this tropical river water confirm the excellent laboratory studies back home - the filtrate is of higher clarity than Leicester tap water. Keith Machell (Intermediate Technology Development Group) joins us from Zimbabwe to breathe life into a redundant, diesel-driven oil expeller that we have "borrowed".

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We have half a tonne of shelled moringa seed ready for crushing. The seed contains 40 per cent by weight of oil, high oleic acid which is of high quality and high market value. More significantly, the presscake remaining after oil extraction still contains the charged proteins responsible for coagulation. This must be the economic driving force for implementation. Malawi, in common with most of the developing world, is not self sufficient in vegetable oil.

THURSDAY. (Week 3, Colombo, Sri Lanka). Reach conference venue 24 hours late. Conference paper is very well received. Spend a few post-conference days travelling the island in search of moringa trees with great success. This must be my favourite country.

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FRIDAY. (Week 4, Tamil Nadu, India). This is the MECCA of MORINGA! Hectare on hectare of flourishing moringa plantations abound - this is a major vegetable crop in the region.

Renew acquaintance of Paramasivan, the South India representative of Water Aid. Survive pillion ride during early morning rush hour of Tiruchchirappalli to breakfast on superb moringa cuisine - much to the delight of the Paramasivan family (flowerbuds, chopped leaves and vegetable pod dishes).

Whisked off in the afternoon to have an audience with the state minister of agriculture who has arrived with his entourage to hold court with local dignitaries. He expresses real enthusiasm and interest in our work. In our presence a lackey is instructed to contact prospective hosts at Tamil Nadu University by mobile phone (handset plus estimated 24 metres of connecting cable). Registrar is ordered to provide "absolute attention" over the next few days . . .

Totally unaided, reach, negotiate and enter the first-class cabin of the "Cochin Express" bound for Coimbatore. Professor Thamburaj sends mystery gift to my hotel, wrapped in newspaper and tied with string. Hotel staff greatly amused when package is opened to reveal 1.45 metre long moringa pod. They have developed an annual variety that grows directly from seed and yields in six months.

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SATURDAY. (Week 5, Rajkot, India). Very definitely the rainy season in Gujurat state . . . scheduled oil extraction trials go well until access tracks to village and oil expeller become totally impassable - save for the old goatherd. We retire to another rural oil establishment where the seed is sesame. Exchange national tokens with the chief oil miller - 20 Benson & Hedges at Pounds 2.66 for 266 bidi at 20p.

Contrary to all basic instincts have survived and enjoyed a week as a sober vegetarian. Admittedly by the end the sign "Guests are reminded that Gujurat is a dry state" over my bed was beginning to prove irksome. Exit pneumatic plague zone of Surat with days to spare. Consider myself fortunate to return with only an infected insect bite on left buttock and several million campylobacter bacteria in my digestive tract.

MONDAY. (Week 6) Renew old friendships at the Infectious Diseases Unit at Leicester Royal Infirmary.

Geoff Folkard Lecturer in engineering at Leicester University.

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