317 



therefore not only no advantage, but the contrary, in using wood- 

 spirit, which is not, after all, much cheaper than alcohol. 



2. But the chloroform from these two liquids, when fully purified, 

 is quite identical in all its properties. Its smell, density, boiling 

 point, and action on the system are, in both cases, exactly the same. 

 That from alcohol is, no doubt, more easily purified than the other ; 

 but it also contains volatile oily impurities, which must be removed 

 before it can be safely used. The peculiar oils which adhere to both 

 kinds of chloroform are not identical, or, at least, not all identical ; 

 but they are of analagous constitution and properties. 



3. Soubeiran and Mialhe have examined these oils. They con- 

 tain chlorine, have a disagreeable smell, and, when inspired or smelt, 

 cause distressing headache and sickness. In the case of wood-spirit, 

 some of its own impurities distil over unchanged, and are found in 

 the chloroform. 



4. It is well known that many persons, after the use of chloro- 

 form, have suffered from headache, nausea, and even vomiting, as I 

 have more than once seen. Headache and nausea I have myself 

 experienced, when I have tried different specimens of chloi"oform, 

 without taking so much as to produce the full effect. 



5. Perfectly pure chloroform, such as is now on the table, does 

 not, so far as I have seen or experienced, produce these disagreeable 

 effects. It is, therefore, highly probable that when they occur, as 

 they do with some individuals, from the use of chloroform of more 

 than the average goodness of quality, this depends on the presence 

 of a trace of these poisonous oils. 



6. All good manufacturers of chloroform purify it by the action 

 of oil of vitriol ; which destroys the oils, while, at the same time, ^ 

 part of the acid is reduced to sulphurous acid. The chloroform, to 

 remove this, is then distilled with lime or carbonate of baryta, and 

 is tolerably pure, if the process be well conducted. 



7. But this is not quite pure, and contains a trace, more or less 

 distinct, of the oils. I have found this to be the case with all the 

 best chloroform made here, up to 1849 ; and I have several times 

 seen headache and sickness from the use of such chloroform, which, 

 as we all know, was the best anywhere made. I must add, however, 

 that the quantity of oils was, although variable within certain limits, 

 always, in the Edinburgh-made chloroform, so small, that it was fit for 

 use, and only caused headache,&c., in a few peculiarly sensitive persons. 



