YELLOW FEVER 241 
larvee of other mosquitoes. The borrow-pits along the right-of-way of railroads 
furnish ideal facilities, in many cases, for the breeding of mosquitoes including 
Anopheles. We may mention also the numerous excavations large and small 
made for one purpose or another which, if they have a firm soil, will accumulate 
water and form breeding-places (artificial pools for watering stock are ex- 
amples), and of course stagnant street and roadside gutters and the footprints 
of cattle and horses in moist land and the plow furrows in clayey corn land in 
wet seasons are Anopheles’ breeding-places, dependent absolutely upon civiliza- 
tion. And we must not forget railroad embankments as obstructions to very 
small streams of running water and as the cause of very extensive accumulations 
of fishless waters often swarming with mosquito larve. Thus in very many 
localities it is not surprising that, with an entire lack of anti-mosquito measures, 
the conditions of civilization have greatly increased the possibilities of serious 
malarial troubles when the disease is once introduced. 
With these facts in view, it is interesting to read such a paper as that by Dr. 
C. V. Chapin on “ The Origin and Progress of the Malarial Fever now Prevalent 
in New England ” (Providence, R. I., 1884), in which he traces the spread of 
the disease from shore towns in Connecticut in 1860 gradually over a large part 
of New England, long before the true method of spread was known. Here was 
a typical case of a non-malarious region in which the Anopheles breeding con- 
ditions described above had been continually increasing for years until, the dis- 
ease once introduced into those Connecticut shore towns, found malaria-carriers 
everywhere and its spread was thus assured. Some of these breeding-places are 
even mentioned by Dr. Chapin without a realization of their true significance, 
and in fact the first outbreak in Connecticut occurred near dams and millponds. 
YELLOW FEVER. 
THE SCIENTIFIC DEMONSTRATION OF THE CARRIAGE OF YELLOW 
FEVER BY MOSQUITOES. 
Physicians had been theorizing about the cause of yellow fever from the time 
when they began to treat it. It was thought by many that it was carried in the 
air; by others that it was conveyed by the clothing, bedding, or other articles 
which had come in contact with a yellow-fever patient. There were one or two 
early suggestions of the agency of mosquitoes, but practically no attention was 
paid to them, and they have been resurrected and considered significant only 
since the beginning of the present century. With the discovery of the agency of 
micro-organisms in the causation of disease, a search soon began for some causa- 
tive germ of yellow fever. Many micro-organisms were found in the course of 
the autopsies, and many claims were put forth by investigators. All of these, 
however, were virtually set at rest by Sternberg in his “ Report on the Etiology 
and Prevention of Yellow Fever,” published in 1890. But a claim made by 
Sanarelli in June, 1897, for a bacillus, which he found in 58 per cent of yellow- 
fever cases and which he called Bacillus icteroides, received considerable cre- 
dence. Wasdin and Geddings, of the United States Marine-Hospita] Service, 
in 1899, reported that they had found this bacillus in a large percentage of 
