TRANSACTIONS OF SECTION B. 593 



restricted to observations on their crystalline form and their physiological action. 

 The physiological action of certain alkaloids of an extremely deadly character is 

 remarkable enoxigh to prove a means of their identification when the effect on the 

 human subject is under observation. The first experimental work on the absorp- 

 tion spectra of the alkaloids arose out of a celebrated trial for murder, which 

 engaged much attention in the year 1882. It was proved that the lethal drug 

 administered was aconitine. 



To identify this substance, of which -there are several varieties, it was necessary 

 at that time to resort to physiological tests made upon small animals. 



Such a course alwa)'s affords an opportunity for forensic arguments based upon 

 the evidence adduced. To substitute absolute physical measurements for physio- 

 logical tests seemed to present facilities for securing justice by removing any 

 doubt of the identity of an unknown substance with the nature of one which is 

 known. Alkaloids yield spectra of two kinds, those which do not and those 

 which do exhibit absorption bands, the difference between the two classes of 

 substances being one dependent on the constitution of the nucleus or ultimate 

 radical of the compound. It is possible not only to identify substances, but also to 

 determine the quantity present in a mixture or solution, and this has actually been 

 done. 



Alkaloids which are derived from benzenoid hydrocarbons, pyridine, quino- 

 line, or phenanthrene give evidence of their origin by their spectra. It is 

 therefore advantageous to make a careful study of the absorption spectra of 

 the substances themselves and of the various products derived from them when 

 studying their constitution. It was remarked while the work was in progress 

 that the quinine spectrum curve was probably due to the conjugation of four 

 pyridine or two quinoline nuclei. It is known now to be a substance of a compli- 

 cated structure containing one quinoline nucleus. It differs from cinchonine only 

 by one methoxyl group in the ;;«?-rt-position. Observations made on simple bases 

 differ from those made on substitution products, such as alkyl derivatives, in this 

 respect, that the bases are the more diactinic, while addition products, such as 

 hydrogenised compounds, and also salts of the alkaloids such as hydrochlorides, 

 are more diactinic than the simple bases. It was shown by the "researches of 

 Alder Wright that different preparations of aconitine can yield substances slightly 

 differing in constitution. On examining them it was shown that these prepara- 

 tions yielded different absorption curves the variations in which were due to 

 differences in the constitution of the different preparations. To state a particular 

 case of a well-defined character, the aconitine from aconitum napellus and 

 japaconitine from a Japanese aconite prepared by Alder Wright had practically 

 the same absorption spectrum and yielded similar curves; but that of japaconitine 

 was just what might be expected from a substance with a nucleus of a similar 

 constitution, but about twice the molecular weight of aconitine ; in other words, 

 a condensation of two molecules of aconitine into one — namely, what was observed 

 in the spectra of morphine and apomorphine, a much greater absorptive power 

 with a similar absorption curve. 



It was shown that japaconitine has a constitution modified in such a manner ; 

 it being, in fact, what was termed by Alder Wright a sesquiapoaconitine ; and the 

 formulaj given for these substances are respectively : Aconitine, Cg^H^^NOn ; 

 japaconitine, C^gllggNjOji, which is in agreement with the spectrum observations. 

 It has, however, been supposed by Freund and Beck that the two substances are 

 identical. 



Strychnine andbrucine are two alkaloids evidently closely related, but little 

 is known about their constitution : both seem to contain a pyridine nucleus united 

 to what is probably a pyrrolic nucleus, the two constituting a conjugated nucleus 

 resembling that of quinoline. The difference between brucine and strychnine is 

 said to be simply that the former contains two methoxyls. The absorption curves 

 show a voider difference than this, and it was predicted that strychnine appears to 

 be a derivative of pyridine, but brucine is more probably a derivative of tetra- 

 hydroquinoline, or an addition product of quinoline of the same character, 

 since there is a remarkable similaritv between the curves of the two substances. 



1903. 



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