24 
of Pharmacology of the Hygienic Laboratory. He obtained upon 
purifying the 19.4 grams of adrenalin 5.5 grams of a fine crystalline 
ash-free base of unusual physiological activity with an optical ac- 
tivity of —53.40°.® An additional one-half gram of prac- 
tically ash-free base made a total of 6 grams. There was, of course, 
some loss in the process of purifying, but that tins unusual loss was 
one due not merely to chemical manipulation but rather to the 
impurities eliminated is shown by physiological testing. The original 
sample was checked against the repurified sample and shown by the 
blood-pressure method on cats to be only one-half to one-tliird as 
active. These findings were eventually confirmed by the physiolo- 
gist of the manufacturers and concurred in by them, as is evidenced 
by their voluntarily sending a bill for 6 instead of for 15 grams of 
adrenalin base. 
Having secured an unusually pure sample of adrenalin base to be 
used as a standard, the next problem was to find an anesthetic 
that would not increase the secondary depressing action of adrenahn 
upon the heart and yet maintain a constant state of anesthesia. An 
animal in order to yield a uniform blood-pressure record must of 
course be so anesthetized as to maintain the irritability of the parts 
affected by the drug at not too liigh nor too low a threshold value, 
at a level where absence of pain is assured and yet where motor dis- 
turbances are removed. 
It may not be amiss to speak for a moment of anesthetics that 
under certain conditions seem to fail in these requirements, them- 
selves bringing about results which at first glance might be attributed 
to the effect of adrenalin itself. Anesthesia from urethane and chloral, 
chloretone, and paraldehyde of course have advantages, but the 
stomach puts beyond the control of the operator all subsequent 
adjustment of the degree of narcosis. And I am inclined to think 
that in the latter part of long experiments there may be present a 
condition of too low an irritability, so that small doses of adrenalin 
at first effective are now no longer so. This condition seemed to be 
present in cats anesthetized with urethane chloral, but not when 
under light ether anesthesia. According to Alexander-Lewin ani- 
mals may be chloralized to the extent of annulling all action of 
adrenalin but still leaving the vaso-motor apparatus sensitive to 
camphor. It is reasonable to suppose that drugs with a chloral-like 
action upon smooth an 1 heart muscle even in doses much smaller 
than used by Alexander-Lewin might so depress the irritability of 
“ The optical actiwty of this preparation was determined by Mr. Taveau and myself 
and compares very well with the best measurements that have ever been made, viz, 
those of Korndorfer (43) made for Flacher. Some of the other readings given in liter- 
ature are [a]jj = —32.6° (Jowett), = —43° (Pauly),— 42.25° (Cushny), 
= —50.72° (Abderhalden and Guggenheim) and [^3:]^-*°= —51.40° (Korndorfer) (43). 
