It is well known that the study of medicine should be preceded by the study of anatomy, which teaches the knowledge of the organization of the human body; but this study is difficult and presents numerous dangers. The study of the organs exacts time; their dissection is tedious, especially if intended for demonstration. In this case it almost always happens that putrefaction seizes the subject before the preparation is finished; for, at a temperature above fifteen degrees, it is impossible to preserve a subject more than six days; under this temperature, that is to say, from 0 to 10 degrees, the longest time one can dissect is twelve or fifteen days. But the corpse always exhales mephitic miasmata before all the organs are putrefied, and this emanation of gas is certainly the cause which most frequently determines typhus fever, so destructive to a portion of our studious youths.[13] [13] Out of ten medical students lodging together, and frequently of the same amphitheatre, nine were attacked by this grave malady in the course of last year, and three of them died. Before exposing my own researches upon the preservation of bodies, it was necessary to examine the researches anterior to mine; it will have been perceived by what precedes, that they were of no service to me. Thus, in viewing all that has been effected on this matter, I can find no indications excepting the processes employed in the arts. In our works of chemistry applied to the arts, I have often been able to prove, practically, that muscular flesh, perfectly isolated, easily dries. When it is mixed with gelatine, it easily experiences, on the contrary, putrid fermentation. Geline[14] is the animal matter, which, all circumstances being equal, putrefies the easiest; and which, forming the organs of animals, experiences an alteration more or less prompt, according to the prevalence of a greater or less quantity of water of composition present. Always, then, when we succeed in preserving from putrefaction this animal part, the other parts will be disposed to desiccation. My researches have conducted me to this conclusion. [14] Up to the present, certain animal substances have been considered chemically identical, which are not so: 1, the proper matter of gelatinous tissues not decomposed; 2, the product which results from their decomposition by the action of heat and water; 3, this same secondary product dried. These three compounds were designated by the denomination of gelatine. As I have proved that there is not between them any identity of character, I have named gelatine the animal matter contained in the gelatinous tissues; I have reserved the name jelly to the product of the decomposition of geline, and I have left the name gelatine to glue, whatever may be its purity.