Abstract
The insulation provided by bedclothes of given thermal resistance (tog value) depends on the size of the body insulated. For simple shapes, discs, strips and cylinders, it is always less than the tog value. If the trunk and limbs of a baby are considered to be thermally independent cylinders, each with the bedclothes well tucked in, the net insulation, I, in tog units, is described by (l/I)=0·6/I b + 0·3/I m + 4·5/G, where Ib is the tog value of the bedclothes, I m that of the mattress and G the girth of the trunk in centimetres. I is reduced if the cot is small, if occupation has been brief, and if the bedclothes are loosely draped over the baby. I is increased (perhaps 2·5 times) if the baby curls up tightly. It is concluded that there is little risk of overinsulating a normal baby whose posture is not restricted, but a combination of fever and thick bedclothes might be dangerous.