64 



MISCELLANEOUS PAPERS. 



Table XVIII. — Effect of copper sulfate upon Bacillus caudatus. 







1 part copper sulfate to — 



Duration of exposure to action of copper 

 sulfate. 



Check. 



10,000 

 parts of 

 water. 



50,000 

 parts of 

 water. 



100,000 

 parts of 

 water. 



500,000 

 parts of 

 water. 



1,000,000 

 parts of 

 water. 



hour 



Colonies. 



Sib 



350 



400 



9,000 



Colonies. 



60 















Colonies. 



G80 















Colonies. 



2,100 



1 



1 







Colonies. 



15 















Colonies. 

 70 







6 hours 







24 hours 











Table XIX. — Effect of copper sulfate upon Bacillus rubrum. 



Duration of exposure to action | ^u „„i- 

 of copper sulfate. i ^"^^^• 



1 part copper sulfate to — 



10,000 25,000 

 parts of parts of 

 water. water. 



50,000 

 parts of 

 water. 



100,000 500,000 

 parts of parts of 

 water. water. 



1,000,000 

 parts of 

 water. 



Colonies. 



hour 175 



2 hours 195 



6 hours 50 



24 hours 1, 050 



Colonies. Colonies. 



10 30 















Colonies. 



225 



90 



5 



5 



Colonies. Colonies. 



90 210 















Colonies. 



135 















EFFECT OF CARBON DIOXID ON VIABILITY OF BACILLUS COLI 

 AND BACILLUS TYPHI. 



A careful study of the gas content of both tap and triple distilled 

 water has shown that for the ty|:]^oid and colon bacilli the presence of 

 carbon dioxid in the water is associated with heightened resistance to 

 toxic agents, such as solutions of copper salts, precipitated copper 

 salts, and copper metal. This is the more strange when one considers 

 that the presence of carbon dioxid in water causes the copper to 

 remain in solution, and in case of insoluble copper, either precipitated 

 or metallic, the carbon dioxid serves to bring a considerable amount 

 of copper into solution. It should be noted, however, that water 

 heavily saturated with carbon dioxid is toxic to Bacillus coli and 

 Bacillus typhi. 



A series of experiments designed to test the effect of carbon dioxid 

 on Bacillus coll., the various conditions of triple distilled water with 

 and without copper, triple -distilled water plus calcium carbonate with 

 and without copper, and tap water with and without copper are tabu- 

 lated below. 



Table XX. — Toxicity of copper sulfate to Bacillus coli in the absence of carbon dioxid.^ 



1 



1 part copper sulfate to— 



Duration of exposure to action of copper ; o\.^n\.' 

 sulfate. (-necK. 



10,000 

 parts of 

 water. 



50,000 

 parts of 

 Avater. 



100,000 

 parts of 

 water. 



500,000 

 parts of 

 water. 



1,000,000 

 parts of 

 water. 



i Colonies. 

 hour . 6, 800 



Colonies. 



1,400 







Colonies. 



2,800 







Colonies. 



2,200 







Colonies. 



900 



2 



Colonies. 

 3, 500 



2 hours ' 5 100 



SO 







1 Experiment conducted in Weber resistance glass test tubes each containing 10 c. e. of Avater triple 

 distilled from glass, portions of which had been treated previously with the desired amount of 

 copper sulfate. All tubes inoculated with a 2 mm. loop of culture of Bacillus coli received from. 

 Prof. Theobald Smith. The temperature during this experiment varied from 18° to 22° C. 



100— VII 



