Closely allied to this are the conditions of the body after death, as governed by circumstances which may affect it, and thereby modify the treatment thereof—admitting that different modes of treatment are required by different cases. How, then, is the undertaker to discriminate, if he be not warned beforehand, or if his knowledge does not teach him what course is the best to follow? And how is this knowledge to be gained, if he has not made it a point to study at least that part of the human organism with which he may have to deal? As the different processes given in this book for the preserving and embalming of bodies are founded upon practical experiments, based upon purely scientific principles, it becomes, then, necessary that these principles be fully explained, so as throw sufficient light on points which might otherwise remain obscure. What has been said about anatomy applies equally well to the study of animal chemistry. The constituents of the human body, fluid and solid, have all more or less different properties, as also their composition varies to a great extent. It is, therefore, a point of material importance for undertakers to know and understand their formation, the causes which may accelerate their decay or putrefaction, and also the means which may be employed to the best advantage to counteract their tendency to disintegration. All the points above mentioned being understood, it follows therefrom that the knowledge thus imparted will prove of great utility to the profession, although it may appear at first sight an unwarrantable waste of time and a mass of technicalities. It may also be useful to repeat here certain injunctions as to the dangers to be encountered in the handling of the dead, and also of the proper care to be exercised by undertakers in avoiding to rush heedlessly into danger and aggravate the perils of their calling. The public at large have but a very imperfect idea of the dangerous, and even, in some cases, repulsive, character of our profession. The undertaker, and the perils attending in many instances the discharge of his duties, as a general thing, are very seldom thought of by those outside of the profession. To a great many the business of the undertaker has something dreadful and appalling about it; and without very well understanding themselves the nature of the feeling, it is always associated with the horrible. This impression, which seems to have grown in the minds of the majority, is altogether an erroneous one, which ought to be eradicated from public sentiment. Undertakers, as a class, are men useful to society; their calling, far from being horrible and loathsome, as the ignorant and shallow minded are pleased to call it, is one which requires a great deal of self-denial, and which often brings to the surface the finest traits of human nature.