Studies of high-molecular placental components in connection with pregnancy toxemia; third paper on placental desoxypentosenucleic acid (DNA).

For the etiological study of pregnancy toxemia along our line, Kanno et al.1) and Kanno2) extracted the components from placentas, once de hydrated with alcohol, by boiling with water. However, their preliminary treatment of placentas and manner of extraction both do not appear ap propriate to obtain the substances for the aim of biological examination, because the natural highly-associated state of them is possibly lost thereby. Hence, we have made changes that the fresh tissue is extracted immedi ately and further the products, whose solubility decreases on isolation even by freeze-drying, are applied to the biological experiments at the stage where they are free from impurities but still in solution. The present account deals with the DNA as the first example accord ing to the new plan. Judging from the results of animal experiments, this component is possible to take some part in causing pregnancy toxemia.