630 
Insects and Disease 
Another test in the same year was made by Professor Grassi near Salerno. 
“The objects of this experiment were,” writes Howard, “(1) to afford 
absolute proof of the fact that malaria is transmitted exclusively by the 
bite of Anopheles mosquitoes; (2) to found, on the results of recent research > 
a code of rules to be adopted for freeing Italy from malaria in a few years. 
The experiment consisted in protecting from malaria railway employees 
and their families, living in ten cottages, at the stations of St. Nicolo, Var- 
co, and Albanella, situated along the Battipaglia-Reggio Railway. They 
numbered one hundred and four persons, including thirty-three children 
under ten years of age. Of these one hundred and four individuals, at 
least eleven, including four children, had never suffered from the disease, 
not having previously lived in a malarious district; a certain number, it 
appeared, had not suffered from it in two or three years, and all the others, 
that is to say, the large majority, had suffered from it during the last malarial 
season, some of them even in the winter. During the malarial season the 
health of the protected individuals was good, with the exception of a few 
cases of bronchitis and a case of acute gastro-enteritis. None of these cases 
was treated with quinine. The one hundred and four persons, with three 
exceptions, had remained free from malaria up to September 16th, the date 
of the report.” 
These two experiments alone would be conclusive. Since 1900, however, 
the brilliantly successful results of actual practical measures undertaken 
on a large scale in Africa under the supervision of English experts, and in 
many European and American localities by army, governmental, and munici¬ 
pal authorities, have settled the matter of malaria infection for all time. 
It only remains now to adopt in medical practice everywhere and in the work 
of boards of health, other municipal and country boards of supervision, the 
efficacious methods, well proved, of fighting malaria by fighting mosquitoes. 
An account of some of these methods, together with the facts of the life-history 
of mosquitoes, and information regarding the distinguishing characters 
of the malaria-bearers (Anopheles) and the non-malarial kinds (Culex and 
others), are given on pp. 305 et seq. of this book. In addition I may simply 
say, when in malarial regions avoid the bite of a mosquito as you would that 
of a rattlesnake. One can be quite as serious in its results as the other. 
Mosquitoes and yellow fever.—So much space has been given to the 
account of the relation of mosquitoes to the propagation and dissemination 
of malaria that we can do only scant justice to the mosquitoes in their role 
as disseminators of other diseases. 
Although yellow fever is a plague long known and one much studied, 
so that its diagnosis and its treatment are well understood and are the neces¬ 
sary knowledge of every physician practicing in tropical regions, and although 
we know certainly that it is the result of the growth in the body of a parasitic 
