XXXII. 6. this effect will daily decrease for the first seven days, and will then increase till about the fourteenth day, and will again decrease till about the twenty-first day, and increase again till the end of the lunation.  If a fever-fit from the above cause should commence on the seventh day after either lunation, the reverse of the above circumstances would happen.  Now it is probable, that those fevers, whose crisis or terminations are influenced by lunations, may begin at one or other of the above times, namely at the changes or quadratures; though sufficient observations have not been made to ascertain this circumstance.  Hence I conclude, that the small-pox and measles have their critical days, not governed by the times required for certain chemical changes in the blood, which affect or alter the stimulus of the contagious matter, but from the daily increasing or decreasing effect of this lunar link of catenation, as explained in Section XVII. 3. 3.  And as other fevers terminate most frequently about the seventh, fourteenth, twenty-first, or about the end of four weeks, when no medical assistance has disturbed their periods, I conclude, that these crises, or terminations, are governed by periods of the lunations; though we are still ignorant of their manner of operation.

In the distinct small-pox the vestiges of lunation are very apparent, after inoculation a quarter of a lunation precedes the commencement of the fever, another quarter terminates with the complete eruption, another quarter with the complete maturation, and another quarter terminates the complete absorption of a material now rendered inoffensive to the constitution.

* * * * *

SECT.  XXXVII.

OF DIGESTION, SECRETION, NUTRITION.

I. Crystals increase by the greater attraction of their sides.  Accretion by chemical precipitations, by welding, by pressure, by agglutination. II. Hunger, digestion, why it cannot be imitated out of the body.  Lacteals absorb by animal selection or appetency. III. The glands and pores absorb nutritious particles by animal selection.  Organic particles of Buffon.  Nutrition applied at the time of elongation of fibres.  Like inflammation. IV. It seems easier to have preserved animals than to reproduce them.  Old age and death from inirritability.  Three causes of this.  Original fibres of the organs of sense and muscles unchanged. V. Art of producing long life.

I. The larger crystals of saline bodies may be conceived to arise from the combination of smaller crystals of the same form, owing to the greater attractions of their sides than of their angles.  Thus if four cubes were floating in a fluid, whose friction or resistance is nothing, it is certain the sides of these cubes would attract each other stronger than their angles; and hence that these four smaller cubes would so arrange themselves as to produce one larger one.