Ether, especially with proper preventive precautions, is preferred to chloroform in almost all cases, including those with heart or kidney disease. It is not employed in cases with severe bronchial or pulmonary inflammation, or in very old age, where the ether intoxication might result in rupture of a sclerosed vessel or in some other injury. In brain surgery Horsley prefers chloroform because of the danger of a rise in general arterial pressure from ether and the resultant extensive oozing of blood; while Crile uses ether because of the special danger, in such surgery, of depression of the medullary centers.

When ether fails to bring about muscular relaxation, as in some alcoholics or very robust athletic persons; or when the secretions of the throat are so abundant as to become dangerous, chloroform alone, or chloroform followed by ether, may be employed. It is reported that in hot countries and at high altitudes anesthesia with ether is difficult to obtain; but Squire (Lancet, 1913) reports the satisfactory use of ether, even with the temperature 120o F. in the shade.

Where a very quick and very transitory effect is desired, as in obstetrics, chloroform has usually been preferred. But a number of cases of fetal death from chloroform are reported; and in some cases, though the child is born alive, it never breathes because of the depression of the respiratory center.