R E S E A R C H E S O N M A L A R I A
97
of the parasite is a free-living amoeba
10
. Bignami however, while rejecting
Manson’s version of the theory, adopted King’s, and stated that he had even
made some experiments on the subject in 1894; but these were only referred to
as a past event
29
, and seemed to have been quickly abandoned.
It is probable that these writers would have remained indefinitely in this
position but for the researches of others. In 1895-1897, Sacharoff
23
, Simond
35
,
MacCallum
36
, and myself
32
destroyed the Italian theory regarding the motile
filaments; and then the publications of the 18th December, 1897
38
, the 26th
February, 1898
39
, the 21st May
42
, the 18th June
4I
, the 24th September
43
, and
11th October
46
, completely demonstrated the life-history of this group of para-
sites in mosquitoes; clearly indicated the genus concerned in the propagation
of aestivo-autumnal fever; and gave other details mentioned in section 17.
As all these papers, except those of the 21st May and the 11th October
(which were in fact covered by Manson’s papers of the 18th June and the 24th
September), were published in such a prominent organ as the British Medical
Journal, it is to be assumed that they were from the first known to the Italian
writers, who have always shown a prompt knowledge of the labours of others.
In his first publication
44
, Grassi refers to my work without mentioning my
name or giving references - as if it were then perfectly well-known in Italy.
The later publications of Bignami and Grassi
48
,
47
show that they were quite
intimate with it before they themselves attained any definite results.
Such being the case, in order to follow my work in Italy and elsewhere, all
that was now needed was to determine the genera of my grey and dappled-
winged mosquitoes from such indications as I had been able to give. The for-
mer had been described in two papers, and was most evidently closely allied to
Culex pipiens;
and the latter, in which the aestivo-autumnal parasites had been
shown to develop, were described in 1897
38
as follows:
"The latter are a large brown species biting well in the day-time, and in-
cidentally found to be capable of harbouring the filaria sanguinis hominis. The
back of the thorax and abdomen is a light fawn colour; the lower surface of
the same, and the terminal segments of the body a dark chocolate brown. The
wings are light brown to white, and have four dark spots on the anterior ner-
vure. The haustellum and tarsi are brindled dark and light brown. The eggs -
at least when not properly developed - are shaped curiously like ancient boats
with raised stem and prow, and have lines radiating from the concave border
like banks of oars - so far as I have seen, a unique shape for mosquito’s eggs.
The species appears to belong to a family distinct from the ordinary brindled
and grey insects; but there is an allied species here, only more slender, whiter,
98
1 9 0 2 R . R O S
S
and much less voracious." In the next paper
39
these small insects also are called
"dappled-winged".
At that time in Italy the Culicidae had been carefully studied by Ficalbi in
several works
31
, and it was an easy task for anyone possessing these works, and
also having fresh mosquitoes for dissection, to determine the genus of my
dappled-winged mosquitoes from my description alone. Although I did not
give the entomological criterion of the genus Anopheles (the long palpi of the
female), I gave three other details which sufficed for the identification. First,
the dappled-winged mosquitoes belonged to a group distinct from the grey
mosquitoes (Culex pipiens type). Secondly, both species of this group had
spotted wings ; and still more particularly, one of them (certainly) had exactly
"our dark spots on the anterior nervure". Now it is well-known that very
few Culices and Stegomyiae have spotted wings, while Anopheles almost always
have them. The Anopheles, however, not only generally possess spotted wings,
but the spots are generally four in number and arranged along or close to the anterior
nervure.
Lastly, if any doubt remained the observer would only have to catch
the first spotted-winged female gnat and to examine the eggs within her, when
they would be immediately seen to possess the characteristic boat-like shape,
with the well-known clasping membrane simulating oars on either side.
It is curious that some of those who have written on the subject have over-
looked the fact that the very first Italian mosquito which from its name alone
would be suggested by my description was Anopheles claviger. Two of the
synonyms of this insect are Anopheles quadrimaculatus, Say, and Anopheles ma-
culipennis,
Meigen!
There is, however, no doubt whatever that the Italians detected the genus
of my dappled-winged mosquitoes, because they themselves say so in two of
their articles of November
48,51
. Nuttall admits the fact
74
. But there is reason
to suppose that they recognized the insects long before November.
It was evidently Manson’s paper of the 18th June, 1898 which stimulated
the Italians to renewed activity, because they set to work shortly afterwards.
But their success was delayed by efforts towards originality. Grassi endeav-
oured to find the guilty species of mosquito by its prevalence in malarious
localities. His efforts were a close repetition of mine in the Sigur Ghat - even
his servant was attacked by malaria as mine had been. He discovered three
species of guilty mosquito, namely Culex penicillaris, C. malariae (so named by
him - really C. vexans), and Anopheles claviger - principally (per lo meno) the
first
44
. I
have already shown in sections 11
and 12 how useless it is to attempt
to identify the malaria-bearing species by its preponderance in malarious