18 
tative rather than quantitative studies of such compounds as ami- 
noketone, ethyl- and methyl- aminoketone, and ethyl- and methyl- 
aminoalcohoL Dakin (20, 21) examined analino, o-toluidino, and 
a-naphthylamino-acetylcatechol, finding that small quantities cause 
no rise of blood pressure; piperidine does, though its compounds are 
less active than piperidine itself. He arrives at the generalization 
that the catechol nucleus is necessary to produce a physiologically 
active substance of the type of adrenalin; that it is of importance 
that the hydrogen atoms of both hydroxyl groups in the catechol 
nucleus be unsubstituted. He thinks also that an alkyl group of 
low molecular weight attached to the nitrogen atom tends to pro- 
duce a more active substance than when an aromatic group is 
attached, whereas derivatives of piperidine, heptylamine, and ben- 
zylamine occupy an intermediate position, and, finally, that there 
seems to be a close connection between chemical instability and - 
physiological activity, and vice versa. 
One of the first and most strikingly practical applications of quan- 
titative determinations of adrenalin found in literature is that of 
Hunt (42) (1906). Samples were sent to the Hygienic Laboratory 
for the determining of their relative physiological activity. He 
found that the rise of blood pressure from equal amounts of samples 
A and B were practically the same, about 1.4 to 1.8 times that of 
C; in order to record the same rise of blood pressure from equal vol- 
umes of C and of A and B it was necessary to increase the strength 
of C by about 1.7 times. In a second series four preparations were 
tested; three of these were labeled 1,000 solutions of the active 
principle’’ and one “dried powdered gland.” Preparations C and A, 
from the manufacturers of the first series, were about equal in strength 
and approximately fiA^e times as strong as D. It was possible to pre- 
pare from an ounce of the dried suprarenal gland about 15 fluid ounces 
of a decoction as potent as the active principle labeled 1:1,000. To 
further emphasize the accuracy of the blood-pressure method I 
quote an interesting paragraph from the same paper: “Abel calcu- 
lated that fresh beef’s suprarenals contain at least 0.3 per cent of 
the active principle. One part of the dried gland corresponds, 
according to the United States Pharmacopoeia, to approximately 
six parts of the fresh gland; hence, according to Abel’s experience 
* * * 1 gm. of the dried gland should contain 0.018 gm. of the 
active principle * * * should yield about 18 c. c. of a solution 
corresponding to 1:1,000 of the active principle. As a matter of 
fact, I found that it yielded about 15 c. c. [from blood-pressure data] 
of such a solution, and it is improbable that the gland was com- 
pletely exhausted in my experiments.” 
Sollmann (67) (1906) also examined a series of commercial supra- 
renal preparations and found the relative efficiency to vary consider- 
