Abstract
1. Lesions produced on the osseous system, especially on the craneal bone, of the embyyonating eggs were investigated by loading of Nicotine in different concentration of 1 mg, 5 mg, and 7 mg/cc.
2. Bothh external measurements and those of the sections of the craneal bone nearly always showed figures lower than those calculated by the rate of the dimiuntion in the growth of the femoral bone. And, the fact that there were the eggs of 1 mg and 5 mg loading groups of the 15th day and the 20th day of embyonation frequently observed with measurements comparable to those of the control groups, and that there were some eggs in which to transversal diameter of the craneal fornix showed increase among the eggs of 1 mg loading group, suggest that the findings of the craneal bone have different significance from those of the femoral bone though hydrocephalic changes were not remarkable.
3 In the present experiment, incompleie chondroplasia was recognized on the eggs up to the 15th day of embryonation but the eggs on the 20th day of embryonation, especially those of 1 mg group, showed marked ossification in contrast to the control. It is considered that premature osseous adhesion further advances to the shortening or diminution of the craneal fundus indicating their resemblance to the findings of chondrodystrophia foetalis.
