PRACTICAL\RESULTS OF BACTERIOLOGY. 745 



drink, the disinfection of their hands, etc., we doubt whether pro- 

 tective inoculations will ever come into general use as a measure 

 of prophylaxis against this disease. Certainly they can not take 

 the place of those sanitary measures which have been proved to 

 be sufficient for the prevention of epidemics namely, exclusion 

 by a proper inspection service at ports of entry (" quarantine "), 

 isolation of the sick, disinfection of excreta, general sanitary 

 police of exposed towns and cities, boiling the water used for 

 drinking purposes, etc. 



But it must be remembered that these measures of prophy- 

 laxis, which have undoubtedly resulted in the saving of thousands 

 of lives, are based upon exact knowledge obtained as a result of 

 bacteriological researches. Since the discovery of the cholera 

 spirillum by Koch in 1884, a very large number of skilled investi- 

 gators have devoted themselves to researches relating to it, and 

 especially to questions relating to its resistance to various de- 

 structive agencies. These researches show that it is quickly 

 destroyed by a comparatively low temperature (60 C.), by desic- 

 cation, and by all known germicidal agents. It is especially sus- 

 ceptible to the action of acids, in comparatively dilute solutions. 

 Our measures of sanitary prophylaxis are therefore established 

 upon a sound experimental basis, and the extension of the disease 

 in civilized countries is the result of a failure to apply well- 

 known means of prevention. As a matter of fact, these measures 

 have been successful in excluding the disease from this country 

 during the last two widespread epidemics in Europe, and have 

 enabled sanitarians to greatly restrict the epidemic spread of the 

 disease in those countries into which it has recently been intro- 

 duced. 



The prevalence of typhoid fever has also been greatly re- 

 stricted by measures based upon an exact knowledge of the bio- 

 logical characters of the typhoid bacillus, and if the recommenda- 

 tions of sanitarians were fully complied with there is reason to 

 believe that it would be practically banished from our cities and 

 towns. 



The bacteriological examination of the water supply of towns 

 and cities is now generally recognized as an important matter, as 

 indicating the sanitary purity of the supply. The detection of 

 the dangerous pathogenic species should lead to the disuse of a 

 water for drinking purposes, or to the recommendation that it be 

 boiled before it is used. The presence of certain other bacteria 

 indicates sewage contamination and consequent danger to those 

 drinking the water without proper precautions as to filtration or 

 sterilization. In Berlin, where the water supply is taken from a 

 river known to be contaminated by sewage, it is passed through 

 carefully constructed "filter beds," and expert bacteriologists 



VOL. XLVIII. 54 



