DISEASES. 133 



some of the above-mentioned places — visits our shores only at 

 long intervals, and with little effect. The mortality from that 

 cause has been particularly insignificant among seamen. The 

 most frequent types of the remittent fevers are the bilious, double 

 quotidian, and double tertian, which latter often terminates in 

 the intermittent. 



The most common types of intermittent fevers are the quo- 

 tidian, double tertian, and tertian ; the quartan is of very rare 

 occurrence, but the octan and the quinquedecimal forms are 

 rather frequent. The return of the latter types coinciding 

 generally with certain changes of the moon, many have been 

 induced to ascribe an influence to that planet as connected with 

 the return of this fever. 



Periodical fevers, either remittent or intermittent, are in 

 certain places endemic throughout the whole year; regular 

 epidemical recrudescences, however, occur at certain periods — 

 generally at a change of season. The localities most liable to 

 fever are those skirting the sea, or lying to the leeward of 

 swamps ; the interior districts may be said to enjoy comparative 

 immunity from periodical fevers, and the occasional cases which 

 there occur may, in general, be traced to some direct cause. 

 Though the harbour of Port-of- Spain is to the leeward of the 

 great Caroni swamp, the shipping, nevertheless, is almost exempt 

 from fever. This is attributable to the fact, that no barrier 

 exists to leeward in the shape of land, either level or elevated ; 

 and the effluvia are thus carried away several miles westward 

 before any such obstruction intervenes. 



Individuals inhabiting a salubrious locality are almost 

 certainly attacked with remittent fever by resorting, even for a 

 short period, to a swampy spot ; should they stay there a few 

 I days only, fever will often declare itself even after a return to 

 their former place of residence. It then, generally, terminates 

 in the octan or quinquedecimal form, and may last for months. 

 A change of air and sea-bathing are, sometimes, the only 

 remedies. 



Persons living in marshy districts are very liable to an attack 

 of remittent fever by removal to a healthier locality. Intermit- 

 tent, but remittent fevers particularly, when not attended to in 

 time, or not properly treated, may end in malignant fever, 

 generally in the apoplectic or algid form; this commonly 



