PROCEEDINGS OF SECTION B, — SUB-SECTION, PHARMACY. 131 



Glancing through these figures one might be inclined to say that 

 both samples kept very well considering their constitution, but these 

 were hardly fair tests, and by no means typical of conditions obtaining 

 under actual working in a pharmacy. The effect of the frequent removal 

 of the stopper has to be taken into consideration. I found during these 

 experiments that the sample must be pipetted directly from the bottle 

 otherwise the results were very discordant. 



Mr. T. McCall, Assistant Government Analyst, Queensland, men- 

 tioned to me that this observation concurred with his own. 



To gauge the effect of exposure I allowed samples to stand exposed 

 for various lengths of time. 



In the case of the above-mentioned spirit of nitrous ether which 

 on 31st May last yielded 20*4 c.c. of nitric oxide from 5 c.c at 20*5° C, 

 the same sample on that date after standing exposed in an open vessel 

 for fifteen minutes yielded 16 '2 c.c. of nitric oxide, and after exposure 

 for one hour 13 c.c. of this gas. Another commercial sample which 

 yielded from 5 c.c. 23*3 c.c. of NO, at 22*8° C, after standing for one 

 hour exposed, yielded only 9*3 c.c. of gas. 



Stronger solutions of ethyl nitrite deteriorate proportionately 

 more rapidly. 



Taking all these observations into consideration it appears clear 

 that the deterioration of solutions of ethyl nitrite is chiefly due to 

 evaporation, and they also lead me to believe that the smaller loss 

 of ethyl nitrite observed in the case of liquor ethyl nitrite was due to 

 the greater viscosity of the solvent. 



To put my deductions to the test I prepared three solutions con- 

 taining 3 per cent, by weight of ethyl nitrite. 



No. 1. — Five volumes glycerine to 95 volumes of absolute 



alcohol, B.P. 

 No. 2.— One volume of glycerine to* two volumes of absolute 



alcohol. 

 No. 3.— Equal volumes of glycerine and absolute alcohol. 



The volume of nitric oxide from 5 c.c. of each w^as measured at 

 21° C. without undue exposure, and also after standing exposed for one 

 hour. The factors obtained were as follows : — ■ 



No. 1 

 No. 2 

 No. 3 



The effect of increasing the viscosity is therefore most marked. 



In the case of spirit of nitrous ether a similar improvement in the 

 keeping qualities was observed by the addition of glycerin. Equal 

 volumes of 90 per cent, alcohol and glycerin were put into the receiver, 



E 2 ' 



