20 
to deterniiiie the effect of Tarioiis factors upon their rate of deterio- 
ration. Each of the set of about twenty samples was marked by 
letter or number and submitted to Dixon for physiological testing. 
The residts when examined by Gunn and Harrison revealed that the 
fresh samples of natural and synthetic adrenalin, though of the same 
concentration^ did not possess the same physiological activity, the 
natural product being approximately one-half that of the synthetic. 
These writers in referring to Dixon's tests conclude that since ‘The 
natural substance is Itevorotatory and the synthetic is optically 
inactive, it would appear that only one of the two isomers possesses 
physiological activity." This is the ffrst published statement of the 
kind formd that is supported by experimental data of so rehable a 
character, but Dixon (23'^ in a note in the Pharmaceutical Joirmal 
states that “it was Cushny who fii’st suggested at a meeting of the 
Physiological Society that the synthetic adrenalin might be a mixture 
of the two optical isomers of which the laevo variety alone was 
markedly active." 
Biberfeld (12) repeated his work of 1906 and not only confirmed to 
his ovm satisfaction his earher residts but also criticised imjustly the 
work of Dixon described by Gimn and Harrison. He weighed equal 
quantities of the natural and synthetic base, dissolved each in 0.8 
per cent sodium chloride solution acidified with the calcidated 
amount of hydrochloric acid, and allowed them to stand for eighteen 
days when their vasoconstrictor action was tested upon a rabbit 
weighing 2 kdograms. The rise of blood pressure residtmg from 
intravenous injections of these compoimds is given as follows: 
0.001 mg. natural, rise of S.5 m. m. 0.001 mg. s^mtlietic, rise of 7.0 m. m. 
0.002 mg. natural, rise of 15.0 m. m. 0.002 mg. sAmthetic, rise of 11.0 m. m. 
0.008 mg. natural, rise of IS.O m. m. O.OOS mg. s^mthetic, rise of 19.0 m. m. 
O.OlGf mg. natural, rise of 27.0 m. m. O.OlGf mg. s\mthetic, rise of 27.0 m. m. 
This is certainly insufficient data upon which to base such impor- 
tant conclusions, and more especially is this true when part of the 
data given in itself seems open to criticism. One and five-tenths 
mdimeters difference ia such small blood-pressure changes as occur 
in the first reading and 4 m. m. difference in the second indicate some- 
thing other than mere experimental error. 
Stolz and Flacher (69) (190Sy in criticising Gunn and Harrison's 
article, state that “the two products, synthetic and natmal adre- 
nalm are not isomeric substances but identical structurally. The 
suggestion that synthetic suprarenin is only half as active as the 
natural Isevorotatory suprarenin is incorrect; as otherwise in logical 
sequence the dextrorotatory suprarenin wotdd be entirely inactive. 
TTe made by synthesis a preparation composed of one-half of dextro- 
rotatory and the other half racemic suprarenin. The latter; which 
