106 FEDERAL REPORTER. �acid." The same work says: "Commercial coal creosote consista almost entirelj' of cresylic acid." Although the crude carbolic acid or the creosote directed by McDougall to be used did not contain carbolic or cresylic acid as pure or as concentrated as it was afterwards made, there was no in- vention in using the purer article, provided the prior com- pound was a true soap, developing the properties of the acids referred to. The advance was only one of degree, so far as the use of the acids was concerned. �The specification of the plaintiffs' patent is not limited to hard soap or to soft soap. It extends to any true soap, made of a compound of alkali with oil or fat, and known and used in the arts under the name of soap. In working ont the process of McDougall, and producing the article which such process will produce, a soap is to be looked for. No other conclusion can be drawn from the use of the word "saponifi- able" by McDougall. Professor Morton testifies that in carrying out McDougall's invention, in exact accordance with his directions, a soap is necessarily produced ; and that the efBcieney, for the purpose named by McDougall, of the com- pound to be produced under his patent, is essentially due to the carbolic and crysilic acids contained in the crude carbolic acid or dead oil or other equivalent substance employed, because those are the only substances present in any notable quantity in dead oil, which are known to have properties sought for by McDougall in his preparation; that is, the power of destroying those low forms of animal and vegetable life which are injurious to sheep. This evidence is not over- borne by any produced on the part of the plaintiffs. �It is satisfactorily shown that by the use of McDougall's formula, as he gives it, employing the "dead oil" he names and caustic soda, a true soap results, in the shape of a soft paste, which, by keeping, becomes a hard soap. It so results, whether the beat is continued to be applied after the fat is added or not. Any one, in practicing McDougall's process, is entitled to use beat and agitation, as used at that time, in saponifying by using alkali and fat, quite as much as in prac- ticing the plaintiffs' process under their patent. The plain- ��� �
