It may also be objected to, with reason that a certain process has been known to work effectually in some cases, whereas the same method employed in a similar manner has proved a signal failure in another instance. To this but one cause can be assigned, and that is the utter ignorance on the part of the operator of the properties, antiseptic and otherwise, of the materials he is employing, also of the different conditions, which will according to existing circumstances modify their action and govern their effect. To use a certain preparation simply because it is highly recommended by some, without knowing the constituents thereof, is very little short of foolhardiness. How is it possible for the operator to employ it with discrimination and judgment? Should he be successful, well and good; the end would be obtained without he being the wiser for it. Should it be otherwise, and the result prove unsatisfactory, how is he to account for the failure, and how to guard against a repetition of the same in the future? A good embalmer, one that really understands his business, does not have recourse to ready-made preparations for preserving bodies; but he chooses the chemicals according to the properties each is known to possess. His experience of their relative actions teach him beforehand how they will work out the result he anticipated. I do not mean that every undertaker and embalmer should be an Orfila in regard to Chemistry, nor is it expected that his knowledge of Anatomy should enable him to fill the chair of demonstrator in a dissecting room, but to achieve real, legitimate success, an embalmer ought to possess a thorough knowledge of the drugs he is manipulating, their individual effects, singly and collectively, and under different circumstances, upon subjects of different natures. A certain amount of the acquaintance with the anatomy of the human body is not only required, but strictly necessary; a gash of the knife upon some vessel of the arterial system might jeopardize the success of an otherwise satisfactory operation. It is this rudimentary knowledge of Physiological Chemistry and Anatomy we shall endeavor to explain in this book, with complete instructions upon the best methods which have been heretofore and are now employed in the preservation of bodies. THE LABORATORY. Before fully entering upon the subject of Embalming, it may not be out of place to make mention of the room devoted to that purpose. As a general thing, undertakers will find it to their advantage to have set aside, either in the rear part of their store or at some other convenient point of the building, a room of moderate dimensions, exclusively for the purpose of preparing bodies. It may also be used either for the purpose of holding inquests, post mortem examinations, and as a morgue.