282 A^umls Entomological Society of America [Vol. IX, 



of malarial attacks, although his camp has the most malarial 

 mosquitos, shows less fever than the Spaniard. This low per- 

 centage is due to a partial immunity "earned" through several 

 previous attacks. I mean by partial immunity more particu- 

 larly the absence of high fevers; the majority of the laborers 

 whose blood teems with crecents but have no fever, do not 

 present themselves for treatment. Only those cases which 

 come to the office of the District Physician enter our statistics. 

 Another interesting peculiarity is observable; although the 

 Spaniard is more susceptible to malaria than is the West Indian, 

 his rate is lower. This is due to the fact that the Spaniard 

 makes liberal use of the liquid quinine freely dispensed at the 

 messes and places of work, thus reducing and eliminating much 

 malaria. The Spaniard looks upon malaria as just so much 

 money lost; the West Indian is of a much livelier nature, not 

 caring if he is losing money. 



No few cases of malaria among the West Indian are repeti- 

 tions, i. e., a recurrence of the fever after the patient left the 

 hospital. Our hospitals cannot take care of malarial cases for 

 a period longer than after the fevers subsided and the blood 

 smears reveal no crecents or but a few. The patient is always 

 advised to continue quinine treatment for at least a month after 

 dismissal. It should be made clear that the figures presented 

 are for the dry season period, and do not include the high 

 increase in malaria from May to November, and hence may be 

 considered as true indexes of actual susceptibility. 



SUMMARY. 



The observations reported are applicable largely to tem- 

 porary construction camps in malarious regions, and unless 

 permanent settlements are in view, screening, traps and mos- 

 quito catching indoors will suffice to keep malaria at a very low 

 rate. However, a certain amount of control work must always 

 be done at larval habitats of the mosquitos. The degree of 

 such anti-malarial work (ditching, fills, etc.,) will depend 

 entirely upon whether the locality is to become a permanent 

 settlement, or whether that locality, if untreated, would prove 

 a serious menace to other localities. 



Traps should at first be placed on all four sides of buildings 

 to determine which side attracts the most mosquitos. Our 



