69 
1-base, is much less toxic. It would seem that the substitution of 
h}^drogen of the amino group by a methyl or ethyl group increases 
the toxicity ; certainly the ethyl group does this, as is shown b}^ the 
increased toxicit}^ of 1- and dl- adrenalin. It would be interesting 
to test the effect of using different alkyl groups in displacing the 
Iwdrogeii of the amino group for I am quite certain that if other 
radicles or more of them were introduced the toxicit}" would be 
greatly altered. 
The four compounds, all catechol derivatives, possess pharmacolog- 
ical qualitative properties that are very nearly identical, but their 
quantitative properties differ widely. What is the key to this quanti- 
tative difference ? Dakin and others have attributed the similarity in 
action to the catechol radicle, winch is essential to produce a rise of 
blood pressure. Daldn would divide the adrenalin molecule into two 
parts, the catechol nucleus and the side chain, oxyethylmethylam- 
ine. It was first shown that catechol itself is qrute active and that 
methyl-amino-acetyl-catechol is still more hke adrenalin. Further- 
more, it was observed that if the hydrogen of the hydroxyl groups 
were displaced, this compound became inactive. Then, again, the 
methyl ether of catechol is inactive. Xow, in the three compounds — 
OH 
OH 
1 
C 
1 
c 
/\ 
/\ 
HC 
C-OH 
HC 
C-OH 
HC 
CII 
HC 
CII 
C 
II 
CH.3 XII(CH3)-HC1 
on 
c 
dl 
!/ 
C CID XH^- HCl 
on 
Ortho-dioxy-pheuyl-ethanol-methyl-amin 
hydrochloride. 
(1) (Dl-adrenaliu hydrochloride.) 
OH 
C 
II(^\-OH 
HC CII 
CO.CII,.XH(C.3ll5):HCl 
Ortho-dioxy-phenyl-ethanol-amin 
hydrochloride. 
(2) (Arterenol hydrochloride.) 
Ethyl-amino-aceto-eatechol hydrochloride. 
(3) (ITomorenou hydrochloride.) 
