SECT. XXXVI. 3. i. OF DISEASES. 355 



lunar periods, i The periods of female menftruation are con- 

 nected with lunar periods to great exaftnefs, in fome inftances 

 even to a few hours. Thefe do not 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 Sedh XXXII. 

 No. 6. their return is immediately caufed by deficient venous 

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

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

 When the catemenia returns fooner than the period of lunation, 

 it (hews a tendency of the conftirution 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 mod powerful lunations at the ver- 

 nal or autumnal equinoxes ; but if it be difappointed of its ob- 

 jecl, it is faid to recur at monthly periods ; in this refpecl: re- 

 fembling the female catamenia. Whence it is believed, that 

 women are more liable ro become pregnant at or about the rime 

 of their catamenia, than at the intermediate times; and on this 

 account they are feldom much miltaken in their reckoning of 

 nine lunar periods from the lalt menftruation ; the attention to 

 this may fometimes have been the caufeof fuppofed barrennefs, 

 and is Therefore worth the obfervation of thofe, who wifh to 

 have children. 



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

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

 nodlurnal cold, are di feu fled in Sel. XXXII. 3. Thofe which 

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

 Section XXXIL 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, (hould raiie the 

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

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

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

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

 or of the lunation, or of the year, fome actions of our fyftem 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 aclion of the af- 

 fecled organ, and of confequent convullion. 



i. A diurnal fever in fome weak people is diftinftly obferved 

 to come on towards evening, and to ceale with a moid (kin early 

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



conftitutions 



