OPINIONS OF HIPPOCRATES. 1049 



The reason why the paroxysms of intermittent 

 fever return at nearly regular intervals of time, 

 must obviously be sought in those general laws 

 of periodicity which mark the revolutions of the 

 animal economy in health, under the influence 

 of season, changes of temperature, day and night, 

 sleeping and waking ; all of which modify the 

 various functions in a regular and uniform man- 

 ner. This tendency to periodicity is strikingly 

 exemplified in many of our artificial habits, which 

 have been termed " second nature." For instance, 

 if an individual accustom himself to remain awake 

 until three o'clock in the morning for several 

 weeks or months, and to rise at ten, it will be 

 some time before he can go to sleep at an earlier 

 hour, although he may rise at seven in the morn- 

 ing ; and so of many other acquired habits, all 

 of which, however, are subordinate to the revo- 

 lutions of nature. 



In accordance with the general theory of the 

 ancients, that fever is owing to a redundancy of 

 bile, it was maintained by Hippocrates, that the 

 tertian, quotidian, and continued forms of the 

 disease are determined by different quantities or 

 degrees of vitiation of the biliary secretion ; and 

 that quartans are owing to an excess or viscid 

 state of what he called black bile.* (Natura 

 Hominis, v. vi. xxviii.) 



* He further maintained, that fever is an effort of nature to 

 expel morbific matter from the body by vomiting, purging, sweat- 

 ing, urine, spontaneous hemorrhage, cutaneous eruptions, tumours, 



