Sect. XXXVI. 3. 1. OF DISEASES. 355 



lunar periods. 1 . The periods of female menftruation are con- 

 nected with lunar periods to great exactnefs, in fome inftances 

 even to a few hours. Thefe do riot commence or terminate at 

 the full or change, or at any other particular part of the luna- 

 tion, but after they have commenced at any part of it, they con- 

 tinue to recur at that part with great regularity, unlefs difturbed 

 by fome violent circumftance, as explained in Sect. XXXII. No. 

 6. their return is immediately caufed by deficient venous ab- 

 forption, which is owing to the want of the ftimulus, defigned 

 by nature, of amatorial copulation, or of the growing fetus. 

 When the catamenia returns fooner than the period of lunation, 

 it fhews a tendency of the constitution to irritability -, that is to 

 debility, or deficiency of fenforial power, and is to be relieved 

 by fmall dofes of fteel and opium. 



The venereal orgafm of birds and quadrupeds feems to com- 

 mence, or return about the moft powerful lunations at the vernal 

 or autumnal equinoxes j but if it be difappointed of its object, 

 it is faid to recur at monthly periods ; in this refpett refembling 

 the female catamenia. Whence it is believed, that women are 

 more liable to become pregnant at or about the time of their cat- 

 amenia, than at the intermediate times ; and on this account 

 they are feldom much miftaken in their reckoning of nine lunar 

 periods from the lad menftruation ; the inattention to this may 

 fometimes have been the caufe of fuppofed barrennefs, and 13 

 therefore worth the obfervation of thofe, who wifti to have 

 children. 



III. We now come to the periods of difeafed animal actions. 

 The periods of fever-fits, which depend on the ftated returns of 

 nocturnal cold, are difcufied in Seel;. XXXII. 3. Thofe which 

 originate or recur at folar or lunar periods, are alfo explained in 

 Section XXXII. 6. Thefe we {hall here enumerate •, obferv- 

 ing, however, that it is not more furprifing, that the influence of 

 the varying attractions of the fun and moon, mould raife the 

 ocean into mountains, than that it mould affect the nice fenfi- 

 bilities of animal bodies ; though the manner of its operation on 

 them is difficult to be underftood. It is probable however, that 

 as this influence gradually leiTens during the courfe of the day, 

 or of the lunation, or of the year, fome actions of our fyflem be- 

 come lefs and lefs ; till at length a total quiefcence of fome part 

 is induced ; which is the commencement of the paroxyfms of 

 fever, of menftruation, of pain with decreafed action of the af- 

 fected organ, and of confequent convulfion. 



1. A diurnal fever in fome weak people is diftinctly obferved 

 to come on towards evening, and to ceafe with a moift fkin early 

 in the morning, obeying the folar periods. Perfons of weak 



conftitutions 



