EXPERIMENT STATION REPORTS. 



175 



with cleaning solution (60 grams potassium dichromate, 60 c. c. sulphuric acid, 

 and lOOOcc. water) to get rid of the excess of alkalinity, free it of organic 

 matter, and destroy the resistant spore-forming bacteria, if any are present. 

 Accordingly a third set of the same glassware was obtained from stock and 

 first treated with cleaning solution as follows: The glassware was filled with 

 the cleaning solution, heated 30 minutes in flowing steam, rinsed five times in 

 tap water and once in distilled water. It was then treated as in procedure A. 

 This was done to see what effect the cleaning solution had on the glassware 

 in influencing the hydrogen-ion concentration of the buffered and non-l^uffered 

 solutions after autoclaving. (Sets Ic, 2c, 3c, 4c, 5c and Oc, tables 1 to 6.) 



EXPERIMENTAL W^ORK. 



Soft glass test tubes were divided into sets and marked set la, set lb 

 and set Ic. Each set was run in triplicate as outlined in procedures A, B 

 and C. The results arc shown in ta})le 1. 



T.\BLE I. 



TABLE 2. 



Sets 2a, 2b and 2c, table 2, were hard glass test tubes run in triplicate according to procedures A. B. and C. 



