The modified Auvard incubator is easily made; the accompanying illustrations (Figs.

5, 6, and 7) explain its mechanism.

Several improved incubators have been described in recent years, but the Auvard appears to be the most satisfactory.
The question of retardation of labor, like that of premature birth, is open to much discussion, and authorities differ as to the limit of protraction with viability.

Aulus Gellius says that, after a long conversation with the physicians and wise men, the Emperor Adrian decided in a case before him, that of a woman of chaste manners and irreproachable character, the child born eleven months after her husband's death was legitimate.

Under the Roman law the Decenviri established that a woman may bear a viable child at the tenth month of pregnancy.