MAY I briefly supplement my letter on this subject in NATURE of February 2? I should like to ask if it is known whether many of the particular grazing-grounds of cattle among which independent outbreaks of this disease have occurred had been re-converted from arable to pastoral land lately; for example, since the intensive crop-production of the War-time? Further, if any such agreement should be apparent, whether any particular crop, or type of crop, more than another had been under cultivation? If information upon these points is available or could be obtained, consideration of the data afforded might, perhaps, yield useful results bearing on the view I have indicated.