A seasoned expedition leader of my acquaintance tells an apocryphal yarn: a young man out in the African bush turned in one night without first checking his sleeping quarters. Curled up under the rucksack which he was using as a pillow was a poisonous snake. During the course of the night, the man's tossings and turnings aggravated the sleeping snake, which bit him.
Later the man woke up to find his head swelling like a football. His expedition medic, at a loss to know the cause, gave him two painkillers and told him to go back to bed. It was only the next morning when man and snake decided to get up at the same time that he realised what had happened.
The moral of this story is not merely to check your sleeping bag for unwanted guests, but also that good first aid in the field can save lives. In this case, immobilisation and paracetamol did just that.
This is reinforced in the Royal Geographical Society's authoritative guide, Expedition Medicine, which has a chapter on venomous animals, containing much reassuring advice on what to do if you happen to find a set of fangs attached to your forearm.
An expedition won't get far if its members start dropping like flies. This book, edited by experienced expedition medics David Warrell and Sarah Anderson, has enough information to treat medical problems in the most challenging environments, from polar ice caps to Sumatran jungle. But, more importantly, it tells you how to avoid them in the first place.
There are four sections. The first covers pre-expedition planning: what do you need in a first aid kit? Are your cardio-pulmonary resuscitation skills up to scratch? Do you have adequate insurance?
The second looks at field medicine itself. This is the area which is likely to be of most relevance for teachers on school trips, when they are required to take the role not only of group leader but also medical officer.
The chapter on camp hygiene and health is particularly sound. Some of it may seem self-evident - "People use a lot of water . . . make sure your containers are small enough to be carried without too much effort" - but such matters are often overlooked.
Further sections become more specialised, covering health problems associated with environmental extremes: tropical and desert trips; high altitudes and mountaineering; even caving, canoeing, kayaking and rafting expeditions. Plenty of school groups go on such trips.
There are emergency check-lists, with diagrams, further reading and useful addresses. The language throughout is refreshingly non-technical and easy to understand.
If you ever venture off the beaten track, either on your own or with a group, this is the next best thing to taking a qualified medic with you. Snakes? Just don't panic, it says here. Must remember that one.