Three years ago a series of experiments were begun with guinea-pigs in order to test the possibility of modifying the type of development in mammals, so as to produce definite monstrosities, as had been accomplished with lower vertebrates. This primary object has not been fully attained at the present time, yet the experiments have demonstrated several points concerning injury of the germ cells, and have shown that an alcoholized male guinea-pig almost invariably begets defective offspring even when mated with a vigorous normal female. A method has been devised for administering the alcohol by inhalation. The animals inhale the fumes of 95 per cent. alcohol which are readily taken into the pulmonary circulation, and very soon cause a state of intoxication. By this method the stomach is not injured and the general metabolism of the animal is maintained in a healthy condition. Few changes are produced in the tissues of the animals, even after a treatment given six times per week has extended over almost thr...