Aside from its well-known purgative qualities, Mrs Oldroyd Hulme says that rhubarb is high in fibre, potassium, natural oestrogen (which helps prevent brittle-bone disease in women) and low in calories.
The pulse then slows as we follow Merivel through his epicurean excesses at court, his purgative sojourn among the Quakers, his selfless struggle against the plague, and his own restoration to royal favor.