R E S E A R C H E S O N M A L A R I A
99
places; and it has now been demonstrated that even in Italy there is no such rela-
tion between the disease and its agent.
Anopheles abound where there is no
malaria - even round Liverpool. Needless to say then, two out of the three
species isolated by Grassi have nothing to do with the disease. He was right
regarding the third, A. claviger; but it is quite reasonable to suppose that he
detached this simply from my description of the dappled-winged mosquitoes.
As a matter of fact all these epidemiological efforts of Grassi, though interest-
ing in a small way, were nothing but a series of vague speculations.*
Meantime Bignami, after four year’s inaction, had returned to his old meth-
od of attempting to infect men by the bites of mosquitoes brought from mala-
rious places. His results are minutely recorded in his paper
48
. He set to work in
August - that is, after Manson had proclaimed at the British Medical Associa-
tion that I had succeeded in infecting birds by the bites of mosquitoes
43
. Big-
nami’s task was now vastly simplified; with the guidance of my work he
collected his mosquitoes from infected houses; whereas if he had continued to
act in accordance with his own theory he would have collected them from
marshes - which would have led to constant failure (section 13). He claimed
his first success early in November, but still could not say which of the various
kinds of mosquitoes employed by him had produced the result.**
Up to November therefore the Italians had failed either to find the guilty
species of mosquito or to demonstrate the life-cycle of the parasite in the in-
sects. At this point Charles’s series of eight letters addressed from Rome to me
(dated from the 4th November to the 14th January) commence. They have
been printed by me with his consent; and show clearly (what however can be
also demonstrated from their own writings) that the Italians were then inti-
mately acquainted with my work; that they had received my report
42
giving
full details of technique: and that they had detected the genus of my grey mos-
quitoes (from specimens sent by Manson) and of my dappled-winged mos-
quitoes (from my description). In his letter of the 8th November, 1898, Man-
* The writers of some zoological text-books, who have evidently had little personal ex-
perience of the disease, seem to have actually believed that Grassi determined the "Ano-
pheles
malariferi" by these efforts. That is not the case. In an early work
54
I said that they
were made independently of Manson and myself; but this was written before I
studied
the Italian work with close attention; and since then I have withdrawn the statement
72
.
** That human malaria is conveyed by the bites of mosquitoes had of course been proved
- practically to a certainty - by my infection of numerous birds three months previously.
Bignami’s experiment was merely a formality of which the success could already be fore-
told with confidence. The statement, frequently made, that he was the first to give exper-
imental demonstration of this fact may be set aside without comment.
100
1 9 0 2 R.R OS S
son records having sent some of my preparations to Charles and Bignami (on
or before that date); and Charles in his letter of the 25th November records
showing one of these to Grassi (on or before that date). It is possible, however,
that the Italians had seen my preparations long before this, as numbers of them
had been sent to Manson and Laveran in the spring and summer; and they may
also have seen those of Koch, who had cultivated Proteosoma in Rome in Sep-
tember.
Bignami, Bastianelli, and Grassi had now evidently determined to resort to
the correct method for determining the guilty species of mosquito,
and imi-
tated exactly the experiment by which I had ascertained the second host of
Proteosoma
in the previous March. The experiment was recorded by them on
the 28th November
51
. They fed six Culex pipiens, one Anopheles nigripes and
four
Anopheles claviger on some cases of crescents, and at last found my pig-
mented cells in two of the last species. They do not record the exact date on
which this observation was made, but from Charles’s letters it would appear
to have been on the 25th November or later.
This, if correct, was the first definite demonstration of the guilty species of
mosquito in Italy. It was made fifteen months after my original demonstration
of the same parasite in the same genus of mosquitoes in Secunderabad on the
20th August, 1897
38
, and nearly four months after Manson had announced the
whole life-cycle of
Proteosoma at the British Medical Association
43
. The Italian
experiment was, however, of doubtful correctness, because the authors do not
state that the mosquitoes used by them had been bred from the larvae
51
. At the
same time they actually impute to me the very
fault which they themselves
were committing, and do so contrary to the printed evidence of my own
words.*
In their next paper
53
they claim to have found the various developmental
stages of the aestivo-autumnal parasites in A. claviger caught in houses and
stables, or fed on patients in hospital. Here again, examination of the publica-
tion shows that none of the insects employed seem to have been bred from the
larvae; and, what is still more important, the number of insects on which the
observations were made is not exactly given. For all we know, the whole
paper may have been written on the strength of only a very few positive re-
sults; and this is the more possible because it describes a life-cycle which is an
* They say that my experiment was doubtful because my mosquitoes may have previ-
ously bitten other animals
51
. Now it is clearly stated in my publications* that the insects
used by me had been bred in "bottles from the larvae"; and from the whole tenor of my
researches it was evident that such was the case.