The European Patent Convention bars the grant of a patent if that which is claimed has previously been "made available to the public". Previous case law has held that such availability exists if an object has been supplied to the public without any condition of confidence and the nature of the invention could have been determined and reproduced from such object, for example by analysis, even if no one had actually done so. On the other hand, if one skilled in the art had no means of discovering the internal structure or composition of a product put on the market embodying the invention, the invention had not been made available to the public, even though a product embodying it had been. In the case of Canine coronavirus vaccine/American Home Products Company, the main claim was to a vaccine which was defined in product by process terms. There had been sales of vaccine made by the process specified in the claims prior to the filing date of the application. The Appeal Board hearing the case concluded, however, that the invention had not been made available to the public by such sales because the steps for production specified in the claims were not determinable from the product that had been sold and the product was not reproducible in any reliable manner from any information that could be gleaned from the material that had been sold.