350 ON THE PURIFICATION OF CHLOROFORM. 
I next examined chloroform of Liverpool manufacture, 
which I had in my possession before I received the sample 
from Edinburgh ; it showed no trace of acid or free chlo- 
rine ; it discolored sulphuric acid considerably, but had no 
effect on litmus paper suspended as before. A slight inha- 
lation of it produced no unpleasant effects, and as I have 
repeatedly inhaled and witnessed the administration of 
chloroform of the same maker, with the most satisfactory 
results, I venture to doubt whether the substance which 
blackens the acid is always that which produces the unplea- 
sant effects sometimes attributed to chloroform. 
I next tried the Professor's mode of purification, but after 
its application the reddening and bleaching of litmus paper 
was produced by both preparations. From the Liverpool 
chloriform I had not much difficulty in removing these un- 
satisfactory indications ; but with the Edinburgh I have 
had great difficulty, and I have only succeeded after re- 
peated agitations with sulphuric acid, carb. barytes, milk of 
lime, and several distillations. It remains to be seen 
whether the purification is real — whether it will keep good. 
Professor Gregory gives a second test of the purity of 
chloroform, which he considers still more delicate than the 
former. He states that pure fchloroform leaves no smell 
when allowed to evaporate from the hand, and that impure 
chloroform bears an odor which is generally in proportion 
to its effect in coloring the acid. I infer that the substance 
which blackens the acid is not always the same, because 
the facts are, in my judgment, not so in the samples of which 
I have spoken. I find that dropping the chloroform on 
paper affords the best means of applying the test, and that 
specimen which darkens the acid considerably, [leaves, if 
any, the less smell. I shall be happy to send you speci- 
mens. My first note of the sp. gr. of chloroform is in Nov. 
1847, about the time it was made known as an anasthetic. 
It is 1.485 and 1.489. My next is 1.491, and theLiverpool 
chloroform, of which I have spoken, is 1.495, at 60°. 
