Report on the Bacteriology of Water. 



207 



He found that spore-free bacilli of Bacillus antliracis rapidly die 

 off in tap water ; whereas, in the condition of spores, this organism 

 may remain alive in such waters for nearly a year. 



Staphylococcus pyogenes aureus may live for from ten to twenty, to 

 npwards of thirty days in ordinary and bad waters respectively. 



Micrococcus tetragenus rapidly disappeared in every case in less than 

 four to six days. 



Bacillus typhi abdominalis lived in some cases upwards of fourteen 

 days in the absence of spores, and upwards of thirty to forty days in 

 the form of spores. 



In all these cases the two most important factors were the presence 

 of spores and the temperature ; the bacteria were eliminated the more 

 rapidly the higher the temperature ; they resisted the longer the 

 more they had matured their spores. This was true, assuming that 

 no proteids or other assimilable organic bodies were added to the water. 



None of Meade Bolton's experiments were made with simultaneous 

 presence of water bacteria : on the whole, subsequent researches 

 have shown that the presence of forms which easily flourish in 

 ordinary waters hurries the elimination of the intruding pathogenic 

 forms. 



Heraeus,* in his general conclusions supports those of Meade 

 Bolton in most of the important respects, and especially the rapid 

 increase of individuals of the bacteria in ordinary waters. He insists 

 on the fact that certain forms multiplied in solutions absolutely 

 devoid of organic materials. 



At the same time, he concludes from his experiments that a " bad " 

 water suits the bacteria better than good drinking water ; and this 

 conclusion is of course in accordance with all ordinary experience, 

 since a " bad " water contains relatively much organic matter. 



The important paper by Wolff hiigel and Biedel,t which may next 

 be examined, is full of excellent hints on methods, and of references 

 to work bearing on the subject, and contains several valuable 

 warnings as to sources of error in such investigations. The authors 

 insist that the composition of the water is of importance, and in this 

 respect place themselves in direct antagonism to Meade Bolton. J 

 They employed both pathogenic and non-pathogenic bacteria, and 

 sterile as well as normal waters. 



* " Ueber das Verhalten der Bacterien im Brunnenwasser, sowie uber reducirende 

 und oxydirende Eigenschaften der Bacterien" ('Zeitschr. f. Hyg.,' vol. 1,1886, 

 pp. 193—234) . 



f "Die Termelirung der Bacterien im "Wasser" (' Arb. a. d. Kaiserl. Gresund- 

 heitsamte,' Berlin, 1886, vol. 1, pp. 455—430). 



X We may bere emphasise our previous note that most investigators disagree 

 with Meade Bolton in tbis respect, and we may conclude that the latter lays too 

 little stress on the constitution of the water. 



