INTRODUCTION 
This bulletin gives the results of our studies on typhoid fever 
in the District of Columbia during 1907. Our first report on this 
subject, for the year 1906, is contained in Hygienic Laboratory Bul- 
letin No. 35. 
This year our studies included epidemiological investigations of 
the disease during the typhoid fever season, daily bacteriological 
examinations of the raw and filtered Potomac RiA^er water, bac- 
teriological and chemical examinations of many hundreds of samples 
of the Washington milk supply, laboratory tests to assist in the 
diagnosis of the disease, and examinations of specimens in a search 
for bacillus-carriers, etc. 
Thus far our studies indicate that typhoid feA^er will cease to be a 
“ problem ” in any community liaAung clean water, an uninfected 
milk supply, and in Avhich cases of the disease are treated as danger- 
ous and contagious. 
Certain improA^ements in the situation should be noted. The 
shalloAv Avells haA’e been closed, and during the summer of 1907 
filtered water of good sanitary quality was supplied the city of Wash- 
ington. Bills have been introduced into Congress with the object 
of improving the milk supply. The sewerage system has been prac- 
tically completed. Laws are being enforced for the condemnation 
of insanitaiT dwellings, and to effect other improvements in the gen- 
eral sanitary conditions. 
The case and death rates for typhoid fever in the District of 
Columbia in 1907 were lower than recorded for any preAuous year. 
The improA’ement in the typhoid feA^er situation within certain 
limits should go on from year to year. The price of such improA^e- 
ment, hoAvcA^er, will be well directed and unceasing efforts on the part 
of the local authorities, with the cooperation of the medical profes- 
sion. The Avater must remain of good quality, the market milk must 
be improA^ed, and a greater regard must be had for the contagious 
nature of the disease. 
Attention is called to certain modifications in chart No. 4 of Bul- 
letin No. 35, rendered necessary by a reexamination of the records 
of the health office. Chart No. 3 in this report is based upon records 
furnished by the health officer and giA^es the corrected curve of the 
seasonal preA^alence of typhoid feA^er in previous years. 
( 9 ) 
