As would be expected, changes in the systemic blood pressure involving pressor or depressor reactions associated with peripheral vasoconstriction and vasodilatation tend to produce corresponding changes in the pression within the eye, the intra-ocular pressure. That stimulation of scattered points in the hypothalamus of the cat of rabbit, however, caused bilateral changes in the intra-ocular pressure independently of the blood pressure, wherein, indeed, a rise of intra-ocular pressure could be associated with a fall in blood pressure or vice versa.