In 1764 Dr. John Theobald of London wrote a book containing "everything necessary to be known relative to the nursing of children, from the time of their birth to the age of 7 years; together with a plain and full account of every disorder to which infants are subject, and a collection of efficacious remedies, suited to every disease."
Theobald had this to say about teething.
DIFFICULT BREEDING THE TEETH
Amongst the disorders to which children are subject, there are none as Hippocrates observes, which occasion such grievous symptoms, as difficult dentition. There is great reason to expect the breeding of teeth will be difficult, if the child is continually crying, thrusts its fingers into its mouth, and bites the nurses (sic) nipples; if unequal swellings are perceived in the gums, where the teeth are expected to appear, if the mouth and whole body are very hot, and the child starts much in its sleep, slavering much, and a looseness are no bad signs, when a child is cutting its teeth. The bad and dangerous disorders arising from difficult dentition, are restlessness, gripes, costiveness, green stools, thrush, fevers, suffocating coughs, convulsions, and epilepsies, which often end in death.
The cure must begin by applying a leach (sic) behind each ear, and when the swelling of the gum shows it is time to cut it, which is known by a white speck appearing on the swelling, it should be cut quite down to the tooth, with a penknife, instead of a lancet, to prevent its uniting too soon, and forming a hard cicatrix.