0. Strickland 
251 
with fever and all of four children examined had enlarged spleens. 
Crescents were found in two of these cases. 
Enough has therefore been said to show that the whole population 
here is subject to fever, and the fact that the children of the stationary 
population suffer, and present signs of chronic disease, proves almost 
conclusively that the fever is endemic in Morib. 
Although some of the local residents attributed the fever to various 
causes it was clear to me that we were dealing with malaria. The 
physician who attended one of the patients informed me, moreover, 
that he had found malaria parasites in the blood, and that all the 
clinical symptoms were those of malaria. 
The anoplieline mosquitoes at Morib. 
Having concluded that malaria was endemic at Morib, I proceeded 
to collect and study the mosquitoes which occurred in the locality, 
and captured five species: ludlowi, rossi, umbrosus, sinensis, and 
tesselatus. 
We know that ludlowi (Christophers), umbrosus (Watson), and 
sinensis (Tsuzuki) have all been incriminated elsewhere as vectors of 
malaria, but it does not follow that they serve as vectors at Morib. 
For instance I have found ludlowi, in great numbers, at Pasir Per- 
matang over the river from Kuala Selangor, to mention but one place 
in the Malay States, and yet the natives never have fever there, and 
none of the children had enlarged spleens. Moreover Brooke reports 
that although ludlowi is very common at Cebu in the Philippines, yet 
there is no fever among the inhabitants. Similarly at Jeram, Selangor, 
a village very closely resembhng Morib, except for the additional Malay 
fishing community at Jeram, I found large numbers of umbrosus in the 
fishermen’s huts, although the spleen index of the Malay children (fifty 
examined) was practically nil. Again, in the case of sinensis, at Alor 
Pongsu in the state of Perak, the manager of an estate told me that at 
dusk anophelines came over like a flight of locusts, and I had the 
opportunity of seeing that, figuratively speaking, he was correct (I could 
easily have caught one hundred sinensis in five minutes if I had 
wished); nevertheless the manager’s family, and the children of 
the two hundred Javanese coolies who lived a few yards away, never 
suffered from fever. 
Enough has therefore been said to show that although three reputed 
malaria vectors were present at Morib, we should not be a priori justified 
in saying that any one of them conveyed malaria in that locality. 
