[ 540 ] 

 LXVI. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



[Continued from p. 470.] 



Jan. 17, ESEARCHES respecting the Molecular constitution 

 1850. "■^^^ of the Volatile Organic Bases. By Dr. A. W. Hofmann. 

 Comnmiiicaled by Sir James Clark, Bart., F.R.S. 



Chemists, although all acknowledging the existence of an intimate 

 relation between the vegetablealkaloidsand ammonia,are nevertheless 

 divided in their opinions respecting the nature of this connection, 

 two theories having been propounded upon the subject. According 

 to the one, that of Berzelius, the bases would have to be considered 

 as conjugated ammonias in which ammonia still pre-exists as such ; 

 while according to Liebig's views, these substances are represented as 

 amides, i. e. as ammonia in which one equivalent of hydrogen is 

 eliminated and replaced by an equivalent of a compound radical. 



The researches of the author prove that the theory of Berzelius is 

 inadmissible, at all events for the volatile organic bases, inasmuch as 

 in these substances ammonia ceases to exist as such. They show, 

 moreover, that Liebig's view, although correctly expressing the con- 

 stitution of by far the greater number of the volatile bases known, 

 and presenting, when considered at the time it M'as first propounded, 

 a wonderful anticipation of subsequent discovery, represents never- 

 theless only a special case of a much more general relation. The 

 result at which the author has arrived is, that ammonia is capable of 

 losing either 1 (^Liebig's case) or 2 or '6 equivs. of hydrogen which 

 are respectively replaced by I, 2 or 3 equivs. of the same, or various 

 compound radicals, a variety of substances apparently endless being 

 produced, in ivhich its fundamental property {the basic character) is 

 retained, although inodijied by the number of radicals introduced and 

 their position in the scale of organic compounds. 



In support of this statement, he adduces the artificial production 

 of thirteen new organic alkaloids, formed by a method which affords 

 the means of increasing the number of these substances to an inde- 

 finite extent. This method consists in exposing ammonia to the 

 action of the chlorides, bromides or iodides of the alcohol radicals, 

 which remove 1 equivalent of hydrogen of the latter, as hydrochloric, 

 hydrobromic, &c. acid, while the remaining constituents, assuming 

 the alcohol-radical, give rise to the formation of an organic base 

 which unites with the hydrogen acid. 



By subjecting the new base itself to a similar treatment, another 

 equivalent of the two remaining equivalents of hydrogen may be 

 removed, a second organic base being formed, which in its turn gives 

 rise to a third. 



The changes which the ammonia undergoes in these various pro- 

 cesses may be represented graphically by the following simple for- 

 mulae, X, Y and Z, denoting generally compound radicals. 



