502 Mr. H. D. Dakin. Physiological Activity of [May 29, 
much increased activity, thus differing in this respect very distinctly from the 
mono-alkylamine derivatives. 

Fig. 3.—Rabbit, 2°5 kilogrammes. Carotid B. P. Vagi divided. Urethane. 0-0005 
gramme C,H,(OH)..CO.CH2N(CH,),Cl. Zero pressure 40 mm. below signal line. 
Time = seconds. 
A corresponding base in the aromatic series was prepared from di- 
methylaniline and chloracetylcatechol, but, like the other aromatic bases, was 
not effective in producing rise in blood-pressure. 
It is well known that injection of piperidine is followed by increase in 
blood-pressure (5), and it therefore seemed conceivable that if instead of the 
ordinary amines used in preparing the bases already described, piperidine was 
substituted, one might obtain products with increased activity. Experiments, 
ae showed that aan was not the case. Piperidino-acetyleatechol, 
nod a CH,. Se Den , was found to be decidedly less active than 

the Pecunia ce reek derivative, and its activity was scarcely 
increased upon reduction. 
It is obvious that the experiments recorded, although ranging over a 
number of different types of substances, are very incomplete, yet they seem 
to warrant certain conclusions, and to indicate the lines upon which one must 
proceed if one wishes to synthesise substances whose physiological properties 
more or less closely approximate to those of natural adrenalin. 
