_Sunstroke._--Sunstroke is characterized by a rapid onset, the patient usually complaining of an uncomfortable sense of burning heat and a feeling of dizziness and depression. Nausea, vomiting, and diarrhoea are common, frequently an intense headache, and sooner or later a muttering delirium. The patient's skin is dry and hot, the face is flushed, and the eyes suffused, and a thermometer will show a bodily temperature of from 105 deg. to 110 deg. or even 112 deg.F. In fatal cases it is usually some hours before the patient dies, though sometimes he succumbs almost instantly. When attacked, the patient should at once be removed to some shady place, and should be held in a sitting posture against any suitable object that may be at hand. The clothing should be loosened at once, and every endeavor should be directed towards lowering the temperature of the victim. This is best done by pouring ice-water or the coolest water that can be secured freely over the entire body of the patient. This treatment should be continued until the temperature approaches the normal--the vigor of the measure employed gradually decreasing, as the patient shows signs of getting better. Improvement is shown by a gradual return of consciousness. _Heat-Prostration._--Like true sunstroke, heat-prostration comes on with an extreme suddenness. The patient becomes suddenly dizzy, and sinks to the ground in a state of collapse. The skin is pale and cool, the pulse limp and weak, and the thermometer shows the temperature to be somewhat below normal. The patient should be laid on the ground in a cool, shady place, and stimulants at once given. By far the most efficient of them is a hypodermic injection of morphine and atropine, to which strychnine in appropriate doses may be added. _Guarding against Sunstroke and Heat-Prostration._--Excessive heat is the basis of both of these conditions, but there are many contributing causes which play a more or less important part in their production. Notwithstanding the fact that they are regarded as being different, and that the treatment and symptoms of the two conditions vary widely, there can be no doubt that certain depressing influences, in every way similar, play an important part in their causation.