1905 — 6 .] Standardising Suprarenal Preparations . 167 
there was a slight rise. In blood pressure experiments with a 
mixture of digitalin and nitroglycerin, Marshall * found that, as 
in his perfusion experiments, each drug gave its own characteristic 
action, the nitrite fall of pressure, being a less prolonged effect, 
passed off, and then a digitalin rise was seen. This result was 
corroborated on the isolated frog’s heart. 
Leech f has tested the action of barium nitrite on muscle 
directly. Barium chloride increases the contractile power of 
muscle and causes contracture. In barium nitrite, the two parts 
appear to act independently. The barium action is first evident, 
later the contraction is annulled, and death of the muscle results 
earlier than with barium chloride. 
In the present experiments rabbits were used, and the blood 
pressure was estimated as described above. Nitroglycerin was 
here used in order to get a more rapid effect than that given 
with the sodium nitrite. The preparation used was that of 
Parke, Davis & Co., made up in T ^- grain (0*6 mg.) tablets. 
Adrenalin was injected, ■ 5 c.c. of 1*5 per cent. (fig. 3 a), and 
when the pressure had again returned to normal, the nitrite 
fall was demonstrated with nitroglycerin T ^ grain (0'6 mg.) 
(fig. 3 b). Then an equal volume of solution which contained 
both drugs was injected. 
When adrenalin 0'5 c.c. of 1*5 per cent, was injected with 1 c.c. 
containing 0*6 mg. grain of nitroglycerin, the adrenalin rise was 
almost entirely cut down, and the opposing effect of the nitro- 
glycerin was soon manifested by a very slight fall and then a 
return of the normal pressure (fig. 3 c). The tracing given closely 
resembles a minimal adrenalin effect. Each of the drugs is here 
apparently acting independently, but in opposite directions — the 
greater rapidity of action of the adrenalin showing itself in the 
increase of blood pressure before the nitrite acts. If the amount 
of adrenalin injected be still further diminished (*4 c.c. of 1*5 
per cent, being injected) while the same amount of nitroglycerin 
is used, the effect of the change in proportion is seen (fig. 3d). 
Again, the rapid action of adrenalin causes an increase of pressure 
which is soon abolished by the commencing nitrite action. In 
this case a sufficient amount of nitrite is given, not only to 
Loc. cit. 
t Loc. cit. 
