Distilled Waters qfcmr Pharmacopoeias. 575 



the addition of any spirit, and these were taken as the basis of 

 the following experiments. 



Equal portions of the waters obtained from the oils of dill, 

 carraway, pimento, spearmint and cinnamon were taken, and 

 to one-half the proportion of spirit ordered by the London 

 College was added, the other half remaining in its original 

 state; these were all loosely corked, marked, and placed 

 aside. After remaining six months they were examined, when 

 the spearmint and carraway waters, with the spirit, were found 

 to be distinctly acid, reddening litmus paper and causing an 

 effervescence with carbonated alkalies ; all the others remained 

 perfectly sound, They were again examined after a lapse of 

 twelve months ; the acidity had increased in the previous cases, 

 while the same waters without the spirit, remained perfectly 

 unchanged, and evidenced no signs of acidity. On examina- 

 tion after another twelve months they did not appear to have 

 undergone any further alteration. 



I need scarcely mention, that in selecting the specimens 

 specified, the object was to try the general action of ordinary 

 exposure to the atmosphere on waters varying in their charac- 

 ters and sources, as other samples might have been chosen 

 which would doubtless have become acid as soon, or even 

 sooner than the carraway and spearmint, as for instance, rose- 

 water, elder-flower, orange-flower, peppermint, and penny- 

 royal waters. 



Another point in favour of these distilled waters keeping, 

 was their having been prepared from their respective essen- 

 tial oils, and not from the herb, seed, or bark. It is stated 

 that these waters are liable to become mucilaginous and sour 

 when long kept, and that the small quantity of spirit is added 

 to prevent this ; from tlie foregoing experiments, however, it 

 will be evidently seen to produce a directly contrary effect, 

 and the formulae of the Edinburgh and Dublin PharmacO" 

 poeias will be equally in error on this point. 



It is curious that of the European Pharmacopoeias, that I 

 have looked into during this investigation, not one labours 

 under this error, their instructions being simply to distil the 

 materials with water. 



On searching back through former editions of the London 

 Pharmacopoeia, to ascertain, if possible, whether the formulae 

 had always been the same, and if not, when this erroneous 

 alteration had been effected, I found that in the Pharma- 

 copoeia of 1624 two classes of distilled waters are specified, 

 entitled simple, and compound or spirituous ; the former made 

 without the addition of any spirit, either in the process or after- 

 wards, the latter similar to the preparations entitled spirits of 



