Organon §103

Chronic miasmatic diseases are collective diseases with an extremely large totality of symptoms. The wesen of the many different forms of psoric disease is the same, just as different cases of disease in the same epidemic are, in essence, the same disease. 

Just like the mostly acute epidemics [§102] the chronic wasting sicknesses remain the same as to their wesen. Just as I did with the epidemics, I had to investigate the chronic wasting sicknesses (namely and principally psora) much more exactly than ever before. I had to do this because of the extent of the symptoms in these chronic diseases and also because one patient carries only a part of the symptoms in himself, while a second or third patient, etc. suffers from some other befallments which likewise, as it were, are only a part torn off from the totality of the symptoms that make up the entire extent of the one and the same disease. Therefore, the complex of all the symptoms belonging to such a miasmatic wasting sickness (in particular, psora) can only be ascertained from very many such individual chronic patients. Without such a complete overview and total image, the medicines that are homeopathically curative for the whole wasting sickness (namely the antipsorics) cannot be searched out. These medicines are, at the same time, the true remedies for the individual patients that are suffering from these chronic maladies.