Recent work concerning the experimental production of bullous keratitis has resulted in at least two important conclusions :1 First, the edema fluid in this condition is derived from tears or from some fluid used as a substitute on the outside of the eye. Second, for the production of experimental corneal vesiculation the osmotic pressure of the fluid within the cornea must be greater than that on the corneal surface. From these conclusions have come several discoveries of practical value. Those relating to the therapy of bullous keratitis, together with a description of the pathologic changes in experimental bullous keratitis, will be reported later. There are, however, several incidental observations which would not be appropriately included under the heading of bullous keratitis but which nevertheless have considerable clinical value and may therefore be separately reported at this time.
The first observation to be reported concerns the so-called toxic action on the