142     All crude animal and vegetable substances have a greater or less amount of medicinal power, and are capable of altering man's health, each in its own peculiar way. Those plants and animals used by the most enlightened nations as food have this advantage over all others, that they contain a larger amount of nutritious constituents; and they differ from the others in this that their medicinal powers in their raw state are either not very great in themselves, or are diminished by the culinary processes they are subjected to in cooking for domestic use, by the expression of the pernicious juice (like the cassava root of South America), by fermentation (of the rye-flour in the dough for making bread, sour-crout prepared without vinegar and pickled gherkins), by smoking and by the action of heat (in boiling, stewing, toasting, roasting, baking), whereby the medicinal parts of many of these substances are in part destroyed and dissipated. By the addition of salt (pickling) and vinegar (sauces, salads) animal and vegetable substances certainly lose much of their injurious medicinal qualities, but other disadvantages result from these additions.      But even those plants that possess most medicinal power lose that in part or completely by such processes. By perfect desiccation all the roots of the various kinds of iris, of the horseradish, of the different species or arum and the peonies lose almost all their medicinal virtue. The juice of the most virulent plants often becomes inert, pitch-like mass, from the heat employed in preparing the ordinary extracts. By merely standing a long time, the expressed juice of the most deadly plants becomes quite powerless; even at moderate atmospheric temperature it rapidly takes on the vinous fermentation (and thereby loses much of its medicinal power), and immediately thereafter the acetous and putrid fermentation, whereby it is deprived of all its peculiar medicinal properties; the fecula that is then deposited, if well washed, is quite innocuous, like ordinary starch. By the transudation that takes place when a number of green plants are laid one above the other, the greatest part of their medicinal properties is lost.