500 Mr. H. D. Dakin. Physiological Actiity of [May 29, 
another. Further work is needed, however, before the question can be 
definitely decided. 
As has been already stated, methylamino-acetylceatechol is fairly active in 
causing increased blood-pressure, whilst the activity of its reduction product 
is comparable with that of adrenalin. It seemed to be of interest to try the 
action of the amino- and other alkylamino-acetyleatechols and their reduction 
products. A considerable difference is noticeable in their physiological pro- 
perties, corresponding to differences in chemical structure. Thus, amino- 
acetyleatechol (CgH3(OH)2.CO.CH2N He), and the lower alkylamino-acetyl- 
catechols, ¢.g., the ethyl and di-methyl derivatives, closely resemble the 
methylamino-acetylcatecho! previously described, and their reduction pro- 
ducts are very active. 
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Fic. 2.—Rabbit, 2°5 kilogrammes. Carotid B. P. Vagi divided. Urethane. 0°:0010 
gramme hydrochloride of ethylamino-acetylcatechol. Zero pressure 30 mm. below 
signal line. Time = seconds. 
If, however, one takes a higher member of the same series, ¢.g., heptylamino- 
acetyleatechol, CgH3(OH)s2.CO.CH2N H(CHe)s.CHsg, it is found that whilst the 
ketone base is still active, yet on reduction its activity is but slightly 
increased. 
The base was prepared by the action of excess of heptylamine upon the 
di-acetyl derivative of chloracetylcatechol, and is a white crystalline substance 
melting at 125°, and giving beautifully crystalline salts. 
This result shows that the nature of the alkyl group attached to the 
nitrogen atom is of great importance. If, instead of an aliphatic one 
substitutes an aromatic group attached to the nitrogen atom the changes 
in physiological properties are very marked. The following bases were 
examined :— 
