226 MOSQUITOES OF NORTH AMERICA 
De Vogel’s paper has been criticised in that he produced no direct proof that 
the Anopheles breeding in the sea-water pools are the ones responsible for the 
malaria attributed to them. Furthermore, the species indicated, Anopheles 
rossii, has been shown repeatedly to be incapable of transmitting malaria, the 
parasites failing to develop within it. But recent investigations by Major Car- 
ruthers in the Andaman Islands confirm de Vogel’s conclusion that the Anoph- 
eles breeding in the sea-water pools are responsible for malaria. The species, 
however, is not Anopheles rossii, but A. ludlowtt which greatly resembles it. The 
question is clearly presented in a recent address by Surgeon-General C. P. Lukis, 
Acting Sanitary Commissioner with the government of India, at Bombay, before 
the General Malaria Committee. Speaking of the results of Major Carruthers, 
he says: 
“The first thing that struck him was the remarkable fact that a large num- 
ber of villages were quite free from malaria, in spite of the fact that many of 
them were surrounded by riceland, swamp or jungle, whereas others showed a 
considerable amount of malaria, the spleen rate varying from 25 per cent. to 
50 per cent. Eventually it was noted that what determined the healthiness or 
unhealthiness of a village was its proximity to the sea. Villages near the sea 
were invariably malarious ; those remote from the sea healthy. Even a distance 
of half a mile from the sea was sufficient to insure the endemic index being 0 
per cent. This distribution of malaria was shown by actual measurement to be 
exactly coincident with the occurrence of a particular species of anopheles, 
namely Pseudomyzomyia Ludlowi, which appeared to breed chiefly in salt 
swamps and brackish water, and which was undoubtedly the chief malaria carrier 
in the Port Blair Settlement. 
“ Now so closely does this mosquito, on casual examination, resemble M. Rossii 
that, with reference to these two species, Professor Eysel has remarked upon 
the folly of too nice distinctions in regard to the species of anopheles and the 
transmission of malaria. Yet the existence of two distinct, though closely re- 
lated species of anopheles is the explanation why, in the Andamans, the prox- 
imity to ricelands and swamps is innocuous, provided that these are at a dis- 
tance from the sea.” 
According to these observations, the proposed destruction of Anopheles by the 
introduction of sea-water does not seem to be rational, at least with certain 
species. At all events the specific identity of the Anopheles concerned must be 
taken into account. It appears certain that while some species may breed either 
in fresh or brackish water others occur exclusively in saline water. In certain 
regions good tidal ponds prevent the breeding of Anopheles to some extent and 
may in that affect the malarial rate. In others, where the species which breed 
in salt or sea-water are present, and there are isolated stagnant pools, as has 
been observed at Samarang and in the Andamans, such measures would have 
little effect unless fish were admitted with the sea-water. 
According to C. 8. Banks Anopheles ludlowii in the Philippines breeds in 
both salt and fresh water. Banks gives an account of his observations in the 
Philippine Journal of Science. In an earlier publication he had shown that 
this species breeds in sea-water and claimed that it is a transmitter of malaria. 
In his first paper he stated that this mosquito had never been found in the 
Philippine Islands breeding in fresh water. Later, however, he took a trip to 
