Dr. Mac Culloch on the Lignites. 231 



tuated in the earth, or which possess the highest antiquity, should 

 present most perfectly all the characters of coal, not only in their 

 structure and appearance, but in their chemical nature. And it will 

 thus generally, I believe, be found, that the most deeply seated, 

 here ranked in a geological sense with lignite and not with coal, 

 are the most purely coal ; although it is easy to understand how 

 numerous exceptions may have arisen from other causes of a local 

 nature which it is unnecessary to suggest. Yet among these 

 coals, so considered in a popular view, it will often be observed 

 that there is a peculiar smell on burning not found in the purer 

 coal of the great series ; a smell produced by a mixture of that 

 oil just mentioned, which is obtained from peat and wood, and 

 which indicates a bituminization not absolutely completed. 



Art. II. Observations on the expressed Oil of the Seed of 

 Croton Tiglium. By John Frost, F. L. S., M. R. I., 8?c. 



[Communicated by the Author.] 



Of all the medicines lately introduced, perhaps none has excited 

 more attention than the expressed oil of the seed of the Croton 

 Tiglium. 



In a former Number of this Journal some experiments appeared 

 concerning the component parts of the oil as to inert and active 

 matter, which induced me to repeat them, as well as to make 

 some others which I purpose giving in detail. About five 

 years ago, when the use of this oil was revived, (for it certainly 

 was no new medicine, in proof of which I beg leave to refer to a 

 paper which I published in the year 1822, in the seventeenth 

 volume of the Medical Repository,) it attracted particular notice 

 on the part of the medical profession, on account of the smallness 

 of the dose (one drop) acting with such certainty as well as 

 violence ; indeed I have lately seen a case of enteritis, in which 

 it acted after enemata, colocynth, o/c. had failed. It has been 

 stated with great truth, that one drop, merely applied to the 

 tongue, will produce violent purgative effects. 



