erin,
and some forms of iron.

The poisons formed in the blood by germs in acute diseases are among
the most common sources of headache. In these disorders there is
always fever and often backache, and general soreness in the muscles.
One of the most prominent symptoms in typhoid fever is constant
headache with fever increasing toward night, and also higher each
night than it was the night before. The headache and fever, together
often with occasional nosebleed and general feeling of weariness, may
continue for a week or two before the patient feels sick enough to go
to bed. The existence of headache with fever (as shown by the
thermometer) should always warn one of the necessity of consulting a
physician. Headache owing to germ poisons is also one of the most
distressing accompaniments of _grippe_, measles, and smallpox, and
sometimes of pneumonia.

The headache caused by the poison of the malarial parasite in the
blood is very violent, and the pain is situated usually just over the
eye, and occurring often in the place of the paroxysm of the chill and
fever at a regular hour daily, every other day, or every fourth day.
If the headache is due to malaria, quinine will cure it (Malaria, Vol.
I, p. 258). The headache of rheumatism is owing also to a special
poison in the blood, and is often associated with soreness of the
scalp. If there are symptoms of rheumatism elsewhere in the body,
existing headache may be logically attributed to the same disease (see
Rheumatism, p. 169).

The poison of gout circulating in the blood is sometimes a source of
intense headache.

The headache of Bright's disease of the kidneys and of diabetes is
dull and commonly associated with nausea or vomiting, swelling of the
feet or ankles, pallor and shortness of breath in the former; with
thirst and the passage of a large amount of urine (normal quantity is
three pints in twenty-four hours) in the case of diabetes.

The headaches of indigestion are also of poisonous origin, the
products of imperfectly digested food being absorbed into the blood
and acting as poisons.

Another variety of headache due to poisoning is seen in children
crowded together in ill-ventilated schoolrooms and overworked. Still
another kind is due to inhalation of illuminating gas escaping from
leaky fixtures.

=Headache from Heat Stroke.=--Persons who have been exposed to
excessive heat or have actually had a heat stroke (Vol. I, p. 40) are
very prone to headache