"But this artistic completeness was closely connected with 'the third cardinal virtue' of Hippocratic medicine—the clear recognition of disease as being equally with life a process governed by what we should now call natural laws, which could be known by observation and which indicated the spontaneous and normal direction of recovery, by following which alone could the physician succeed.
"Another Hippocratic doctrine, the influence of which is not even yet exhausted, is that of the healing power of Nature. Not that Hippocrates taught, as he was afterwards reproached with teaching, that Nature is sufficient for the cure of diseases; for he held strongly the efficacy of art. But he recognized, at least in acute diseases, a natural process which the humours went through—being first of all crude, then passing through coction or digestion, and finally being expelled by resolution or crisis through one of the natural channels of the body. The duty of the physician was to foresee these changes, 'to assist or not to hinder them,' so that 'the sick man might conquer the disease with the help of the physician.' The times at which crises were to be expected were naturally looked for with anxiety; and it was a cardinal point in the Hippocratic system to foretell them with precision. Hippocrates, influenced as is thought by the Pythagorean doctrine of numbers, taught that they were to be expected on days fixed by certain numerical rules, in some cases on odd, in others on even numbers—the celebrated doctrine of 'critical days.' It follows from what has been said that prognosis, or the art of foretelling the course and event of the disease, was a strong point with the Hippocratic physicians. In this perhaps they have never been excelled. Diagnosis, or recognition of the disease, must have been necessarily imperfect, when no scientific nosology, or system of disease* existed, and the knowledge of anatomy was quite inadequate to allow of a precise determination of the seat of disease; but symptoms were no doubt observed and interpreted skilfully. The pulse is not spoken of in any of the works now attributed to Hippocrates himself, though it is mentioned in other works of the collection."
*The author of this article in the Encyclopedia Britannica does not see that it is the modern [then as now] orthodox "scientific nosology, or system of disease" which obscures the simplicity and precision of the Hippocratic philosophy of disease and cure.
"In the treatment of disease, the Hippocratic school attached great importance to diet, the variations necessary in different diseases being minutely defined. In chronic cases diet, exercises and natural methods were chiefly relied upon."
These wonderful truths, with other wisdom of the ancients, were lost in the spiritual darkness of the Middle Ages. Modern medicine looks upon these claims and teachings of the Hippocratic School as "superstition without any foundation in fact." However, the great sages of antiquity, drawing upon a source of ancient wisdom, deeply hidden from the self-satisfied scribes and wise men of the schools, after all, proclaimed the truth.
Every case of chronic disease properly treated by natural methods proves the reality and stability of the Law of Crises. It is therefore a standing wonder and surprise to one who knows, that this all-important and self-evident law is practically unknown to the disciples of the regular schools.
The Law of Sevens
In accordance with the Law of Periodicity, the sixth period in any seven periods is marked by reactions, changes, revolutions or crises. It is, therefore, looked upon by popular intuition as an unlucky period. Friday, the sixth day of the week, is regarded as an unlucky day; Friday is hangman's day; according to tradition the Master, Jesus, was crucified on Friday.
Counting from the first sixth or Friday period in any given number of hours, days, weeks, months, years or groups of years, as the case may be, every succeeding seventh period is characterized by crises.
This explains why 13 is considered an unlucky number. It represents the second critical or Friday period.