TOLERANCE FOR ALKALIES IN ASIATIC CHOLERA. 



375 



the 1 per cent solution, but the two stronger solutions were made up 

 without the addition of any other salts. 



The preparation of sterile sodium bicarbonate in large quantities (20 to 40 

 liters) offers some difficulties because of the instability of this salt at the 

 temperatures required for sterilization. The normal carbonate is rapidly formed 

 even at 70° C. When solutions are heated in the autoclave a considerable 

 portion of the bicarbonate is changed permanently to the normal carbonate. All 

 of the concentrations used were sterilized by heat except some of the 2 per 

 cent solutions, which were filtered through porcelain. * 



Estimation of the amount of change occurring during sterilization was made 



bj r titration against -- hydrochloric acid with phenolphthalein. at a temperature 



of 0° C. At any temperature a solution of neutral alkali carbonate is hydrolyzed 

 according to the equation Na • Na C0' 3 + H ■ OH' ^ Na ■ OH' + Na • HCO' 3 

 At ordinary temperatures a sharp end-point can not be obtained, but at 0° 

 the solution may be titrated against hydrochloric acid with phenolphthalein to a 

 fairly exact equilibrium. The concentration of the hydrogen ions from the 

 dissociation of sodium bicarbonate is too low to affect the indicator and the 

 reaction takes place just as if the latter were not present; the amount of acid 

 required for neutralization represents, therefore, only half of the alkali present 

 as normal carbonate. Sterilization was carried on for one hour at 7 pounds 

 pressure in an autoclave connected with live steam. By keeping- conditions 

 constant with regard to pressure and duration of heating, successive lots of 

 solution were obtained which were fairly constant in composition. 



According to the basis of calculation just outlined the average amount of 

 change was as follows: 



After sterilization. 



N.iIICO a, 

 in grams, 

 per 100 cu- 

 bic centi- 

 meters be- 

 fore sterili- 

 zation. 



1.0 

 1.5 



Cubic cen- 

 timeters of 

 N 



jgHC'l re- 

 quired to 



Percent of, 



NaHC0 3 



converted 



neutralized toNa,C0 3 

 i cubic cen- 

 : timeters of 

 alkali. 



1.8 

 2.4 



Grams 

 NaHC0 3 

 per 100 

 cubic cen- 

 timeters. 



0,7 

 1.1 



Grams 

 Na. C0 3 



per 100 

 cubic cen- 

 timeters. 



0.19 

 0.26 



These results do not .represent a chemical equilibrium but show the progress 

 of the reaction under certain given conditions. The fact that a. relatively large 

 amount of bicarbonate remained unchanged notwithstanding the high temperature, 

 might be accounted for by the use of pressure during sterilization which would 

 prevent the evolution of steam from the solution. 



All the patients included in Table V, except numbers 27 and 39, were 

 admitted in complete collapse; one case (number 27) was complicated 

 with an acute, bloody dysentery/ No detailed classification of the 

 condition of the cases was attempted other than the separation into 

 partial and complete collapse. Physical examination is hardly a satis- 

 factory basis for the comparison of different cases; thus the records of 

 the pulse, temperature, blood-pressure, respiration, and the other evidences' 



