In a previous communication evidence was presented which demonstrated that the local application of various irritants can produce large collections of fluid in the skin of ducks.1This observation made possible the study of cutaneous collections of fluid in an experimental animal which is readily available. With the use of the duck, it has been possible to study various dermatologic phenomena. Since the studies could not be continued, it was deemed advisable to present some of our preliminary data in order to demonstrate the value of the aforementioned phenomena in experimental dermatology. The first series of experiments consisted in the determination of the minimal dose of a vesicant necessary to induce blisters in a series of ducks. It was observed that with bis-beta-dichlorodiethylsulfide (mustard agent) dose varies somewhat with the age of the animal. In a series of ducks aged 16 months and over, 0.017 mg. of mustard agent produced localized collections of fluid in the skin, whereas