(f.) Morbi intercurrentes. These are diseases which depend upon causes entirely different from those that occasion the prevailing disease; but they frequently ingraft their character upon the latter, and, by so doing, are apt to transform a naturally mild disease into a dangerous and malignant one.

To this classification of diseases we shall add a few indications which are of great use in examining a patient. In investigating the symptoms of an epidemic or sporadic disease, it makes no sort of difference whether a similar disease has existed previously. The previous disease has no sort of influence upon the present epidemic, which requires to be thoroughly investigated as an entirely new, unknown disease of a peculiar kind. Hahnemann teaches that even measles, smallpox, scarlatina, rubeola, etc. are not exempt from that rule; these diseases depend, it is true, upon the same miasm, but the form of the eruption only remains the same. In all those diseases there is an essential difference as regards the systems which are principally affected, the concomitant symptoms, the prognosis, and the course and termination of the disease.

The physician frequently requires to investigate two or three cases of an epidemic disease before he succeeds in obtaining a correct idea of the totality of the characteristic symptoms which scarcely ever exist together in one case; but even an incomplete knowledge of those symptoms will enable him to administer a remedy with more certainty than an allopathic physician could do. However, although he may feel sure that he has given a remedy which corresponds as nearly as possible to the symptoms so far as he knows them, yet he ought to make it his duty to observe every new case with the same unremitting attention, in order to finally complete his group of the characteristic symptoms of the disease and to be sure that he has selected the true specific remedy.

In thus observing an epidemic disease, the general symptoms, such as loss of appetite, want of sleep, eructations, etc., will be specially and correctly noticed, and the characteristic particular symptoms of the epidemic disease will be found to constitute a limited and rarely-occurring group. These symptoms all originate in the same cause, but their totality can only be known by observing several patients of different constitutions and temperaments.*.

* See Organon, § 100-102.

Stationary diseases likewise require a correct and thorough investigation of all the symptoms which can only be known by observing a number of patients and we will often find that the whole group of symptoms indicates a different remedy from what we might have selected after a merely superficial investigation of the disease. This scrupulous investigation is of essential benefit in intercurrent diseases, where the characteristic symptoms frequently point to the same remedy which corresponds to the symptoms of the stationary diseases in that region.

According to their origin, diseases may be divided into

(a.) Hereditary (morbi hereditarii). These are diseases which have existed in a family for generations past. We have an hereditary scrofulous, hemorrhoidal, phthisical, apoplectic, etc. disposition, which deve-lopes itself in spite of the utmost care in removing all hurtful influences, and frequently leads to the dissolution of the organism, baffling the best directed efforts of the physician.

If the physician should have reasons to suspect the existence of an hereditary disposition, he ought to inquire whether any of the ancestors, parents, brothers, sisters have been affected with a similar disease, or have died with it. If this should be so, he will be much better able to express a correct opinion in regard to the prognosis and to the chances of a cure.

(b.) Morbi congeniti. These diseases generally depend upon malformations with which the individual was born.

(c.) Morbi acquisiti. These are diseases for which the patient had no particular predisposition, but which he brought upon himself by exposing himself for a length of time to hurtful influences, for example: taking hurtful beverages and nourishment, indulging excesses of various kinds which gradually undermine health, being constantly deprived of the necessary means of subsistence, living in unwholesome, marshy regions, or in cellars and close apartments, being deprived of exercise or open air, indulging excessive physical or mental exertions, being continually agitated by unpleasant moral emotions, etc.

No psoric miasm is required to develope such diseases. According to Hahnemann such diseases disappear of themselves if they have not excited a chronic miasm.

(d.) Primary diseases (morbi primarii, protopathici). These are diseases which result immediately from noxious influences, whereas the secondary, consecutive diseases (morbi secundarii, deuteropathiei,) arise from a malady which is already existing. This class of diseases requires no special definition, as their name indicates their character.

(e.) Contagious and miasmatic, and non-contagious and non-miasmatic diseases. A contagium, whether it be originally formed in man or in any other kind of organic body, in animals or plants, is a material substance, the original and exclusive product of a morbid condition of the organism and possessing the power of infecting other individuals of the same kind with an identical or at least very similar disease and of spreading in this way to remote regions. A contagium being dependent upon meteoric and telluric influences, it is most easily developed in times of war, famine and inundation, producing hospital, dungeon and yellow fever, typhus, etc.

A miasm, on the contrary, is a volatile deleterious substance, the chemical composition of which is unknown, which spreads through the atmosphere and incorporates itself with it with more or less tenacity. A miasm frequently arises from decayed organized bodies and from the exhalations of sick persons. People who are forced to live in such a deleterious atmosphere, are necessarily exposed to its influence. Considering the multitude of vitiated exhalations which are concentrated in many places where people have to live, it cannot appear strange that the number of miasmatic diseases should be very considerable. Miasm and contagium frequently go hand in hand, one producing the other, as is the case in smallpox.