_What is the time of their appearance?_

The two central lower teeth are usually the first to appear, and come
from the fifth to the ninth month; next are the four upper central
teeth, which come from the eighth to the twelfth month. The other two
lower central teeth and the four front double teeth come from the
twelfth to the eighteenth month. Then follow the four canine teeth,
the two upper ones being known as the "eye teeth," and the two lower
as the "stomach teeth"; they generally come between the eighteenth and
the twenty-fourth month. The four back double teeth, which complete
the first set, come between the twenty-fourth and thirtieth month.

At one year a child usually has six teeth.
At one and a half years, twelve teeth.
At two years, sixteen teeth.
At two and a half years, twenty teeth.

_What are the causes of variation?_

The time of appearance of the teeth varies in different families; in
some they come very early, in others much later. The teeth may come
late as a result of prolonged illness and also from rickets.

_What symptoms are commonly seen with teething?_

In healthy children there is very often fretfulness and poor sleep for
two or three nights; there may be loss of appetite, so that only one
half the usual amount of food is taken; there is salivation or
drooling, and often slight fever; there may be some symptoms of