Gangrenous mastitis is not an uncommon sequela of severe mastitis and if improperly handled often results in the death of the animal. The prognosis on the life of the animal is usually favorable if treatment is administered as soon as possible after diagnosis even though the affected portion of the udder may be lost.

The study of coumarin derivatives began with the identification of the causative agent in sweet clover responsible for the hemorrhagic disease of cattle now called "sweet clover disease." The investigation of this disease and the isolation of the etiological factor has established both the chemical and physiological properties of dicoumarin.

It is in response to the invitation of Ye Editor that this paper has been prepared. Its object is, in brief compass, to point out some hiatuses in our knowledge of the ovulation process in vertebrates.