170 APPLIED BACTERIOLOGY 



organism which is the cause of enteric fever may, when 

 introduced into potable water of good quality, not only 

 retain its vitality for a considerable period of time, but may 

 multiply almost indefinitely. Therefore the slightest con- 

 tamination with the alvine discharges from a case of true 

 enteric fever may serve to render dangerous millions of 

 gallons of drinking water. Thus, it will be seen that the 

 virulence of typhoid-contaminated water is not necessarily 

 dependent upon the organic impurity of the water, but 

 upon the specific pollution. If this is granted, and. ex- 

 perimental proof may be easily applied,* it will be ad- 

 mitted that under certain circumstances the questioninay 

 arise, Has the epidemic of enteric fever now in pro- 

 gress in a given community had its origin in the water- 

 supply ? 



It must be admitted that the proof of specific pollution 

 in a number of the epidemics of water-borne typhoid rests 

 on a somewhat incomplete basis, as will be seen from the 

 perusal of an interesting series of papers by Dr. E. Hart, 

 which have recently appeared in the British Medical 

 Journal.-f The- bacillus of typhoid fever has, however^ 

 been isolated by many competent observers from water 

 that had conveyed and caused the disease. Some doubt 

 attaches to the identification of the organism by some of 



* A drop of a broth culture of B. typhosus (twenty-four hours old) 

 was weU diluted with sterile water. One c.c. of this diluted culture 

 was added to 200 c.c. of the ordinary tap-water. The number of 

 organisms was then estimated by an ordinary gelatine-plate culture, 

 when 1 c.c. of the water was found to contain approximately 900,000 

 organisms. This amount of pollution was not sufficient to raise the 

 amount of albuminoid ammonia appreciably. The tap- water previously 

 contained only 200 organisms per cubic centimetre. 



t ' Water-borne Typhoid : a History Summary of the Outbreaks in 

 Great Britain and Ireland, 1858 to 1893,' by Dr. E. Hart, British 

 Medical Journal, June 15, 22, 29 ; July 6, 13, 20 ; August 17, 1895. 

 See also reprinted report. 



