§ 143
If we have thus tested on the healthy individual a considerable number of simple medicines and carefully and faithfully registered all the disease elements and symptoms they are capable of developing as artificial disease-producers, then only have we a true materia medica – a collection of real, pure, reliable1 modes of action of simple medicinal substances, a volume of the book of nature, wherein is recorded a considerable array of the peculiar changes of the health and symptoms ascertained to belong to each of the powerful medicines, as they were revealed to the attention of the observer, in which the likeness of the (homoeopathic) disease elements of many natural diseases to be hereafter cured by them are present, which, in a word, contain artificial morbid states, that furnish for the similar natural morbid states the only true, homoeopathic, that is to say, specific, therapeutic instruments for effecting their certain and permanent cure.
1 Latterly it has been the habit to entrust the proving of medicines to unknown persons at a distance, who were paid for their work, and the formation so obtained was printed. But by so doing, the work which is of all others the most important, which is to form the basis of the only true healing art, and which demands the greatest moral certainty and trustworthiness seems to me, I regret to say, to become doubtful and uncertain in its results and to lose all value.