200 BAENETT COHEN 



The influence of soluble glass constituents 



Chemists from the time of Lavoisier have had to consider 

 the question of the solubihty of the glass vessels in their work. 

 That a marked influence upon biological experiments may be 

 exerted by soluble constituents from the container has been re- 

 cognized now and then, but this aspect is yet too often neglected. 



Some biological investigators hke Beneke (1895) and Ficker 

 (1898) have observed marked responses referable to glass con- 

 stituents dissolved in the distilled water they used. MoUsch 

 (1895) tried to eliminate this source of difficulty by coating his 

 vessels with paraffin. Houston (1914) attempted a comparison 

 of containers of different materials upon the viability of bacteria 

 and obtained some striking qualitative differences. Bigelow 

 and Esty (1920), Esty and Cathcart (1921) and Fabian and Stull 

 (1921) observe differences in heat sterilization referable in part 

 to the solubility of the glass containers, and suggest that the 

 result may be due to pH effects. 



Under moderate conditions of temperature, the quantity of 

 material dissolved by water from ordinary laboratory glassware 

 in a short time is comparatively small;' and the most obxious 

 results of such solution are the effect upon the pH of the water 

 and the dissociation of other cations and anions. The results 

 of the experiments reported here show that changes in pH of 

 distilled water may often be quite considerable; and tap water, 

 whether sterilized or filtered, has showTi itself not very different 

 in behavior from distilled water in this respect. 



There are occasional references in the Uterature to a toxic 

 action exerted by distilled water upon microbes. Laird (1919) 

 found distilled water toxic to staphylococci, which fact he con- 

 siders, as does Burgess (1920), to be due to plasmolysis and sug- 

 gests "equilibrated" salt solutions as indifferent suspension media 

 for bacteria. No observations of a similar nature seem to have 

 been reported for bacteria of the colon-typhoid group. Our 

 own experiments demonstrate the prolonged viabihty of these 



• It should be noted that our glassware had been in use for some time and had 

 become "aged" to some extent. 



