There is another feature that the believer in the law of similars should find no insuperable difficulty in accepting as a criterion of the validity of a proving, namely: _the similarity of the drug symptoms to certain disease symptoms_. I am not ready to believe that drug symptoms are only the result of a "fortuitous concourse of atoms," nor can I for one moment imagine that they are the product of blind and aimless chance. I plainly discern in them the result of law, and I am wholly unable to conceive of existing law without the absolutely necessary _pre_-existing law maker. The consequent must have its antecedent. Therefore, in a drug symptom I see a purpose, and by the light of the law of similars I find the purpose of a drug symptom in an analogous disease symptom--they answer to each other as face unto face in the refiner's silver--and behind and beyond them both is another purpose, of wisdom inscrutable, of love unfathomable. In a word, my reader, the problem of the visible universe forces upon me the alternative that weighed upon Marcus Aurelius--"either gods, or atoms." With atoms only I cannot account for law; with God and in God both atoms and law find a meaning and a purpose. If I were submitting these convictions, or, if you will, this "working hypothesis," to a Sir Thomas Browne, or a William Harvey, or a Thomas Sydenham I should feel no momentary hesitation; as it is, I can only hope that the spirit that filled these worthies is not extinct in days when the "spiritual colic" that disordered an imaginary _Robert Elsmere_ is thought to disturb the eternal Verities. I much doubt if they who mistake an eclipse for an annihilation will get any good from this poor pen of mine. The resemblance between the symptoms of angina pectoris and the effects of the poison of _Latrodectus mactans_ are so striking as to justify the presentation of a comparison; and it is hoped that physicians of wide reading will pardon what may seem to them a piece of supererogation for the sake of many a humbler practitioner whose opportunities have not been so happy. At the same time, the widest reader must admit that he has not found any one authority who has given a complete picture of angina pectoris. Nor is it essential that such an all-including "composite" shall now be presented; on the contrary, we shall offer only salient points substantiated by observers of the highest order. It will be well to start from an authority whose scholarship has never been excelled--_Copland_. Of all our medical writers he may be called the _Great Definer_--his readers will know what that means. "_Acute constricting pain at the lower part of the sternum, inclining to the left side, and extending to the arm, accompanied with great anxiety, difficulty of breathing, tendency to syncope, and feeling of approaching dissolution._"