The importance of the "orbital cortex" is nowadays generally recognized, after Spatz ('37) once more called attention to the changes in character following orbital (and basi-temporal) lesions.
The effect of stimulation of the orbital surface upon respiration and circulation was first discovered by Bailey and Sweet ('40), that on the extremities and on the kidney have recently been described by Livingston et al. ( '47).
This makes a knowledge of the connection of orbital cortex with diencephalic centers particularly desirable in order clearly to understand the clinical and experimental observations which have just been briefly mentioned. We are, of course, not quite without information. To mention only the most recent papers concerning the macaque, cortical lesions and subsequent searches for retrograde degenerations were made by Walker ('40) and Marchi preparations after cortical extirpations were studied by Mettler ( '47). All observations agree that the orbital cortex receives its thalamic radiations from the medial nucleus, in particular from the medial part of that nucleus. But, a s in every method, there are sources of error in the method of retrograde degeneration. Walker approached the orbital surface from the lateral side by elevating the frontal lobe and dissecting the cortex subpially. Inadvertent trauma, at least to the lateral edge of the frontal lobe, although un-243