1905-6.] Standardising Suprarenal Preparations. 161 
The results on different frogs were somewhat variable, and further, 
the method of perfusion is tedious and troublesome, especially if 
the preparation to be tested is used after the action of a preparation 
of standard strength. 
2. Minimal Effective Dose on Blood Pressure in Rabbits . — The 
blood pressure experiments were performed by Dr Noel Paton. 
Rabbits of fairly uniform size (about 2000 grams) were selected. 
The carotid artery was connected with a mercury manometer 
in the usual way, and the injections were made into the jugular 
vein. Full anaesthesia by ether was maintained till the death 
of the animal. 
Gradually decreasing doses were injected into the jugular vein. 
The smallest amount which gave a definite and invariable rise 
of blood pressure was 0*5 c.c. of a Off 25 per cent, solution of 
adrenalin (Parke, Davis, 1 in 1000) — that is, *00062 mg. of 
adrenalin, or *0003 mg. per kilo. A similar result was given with 
hemisine and with suprarenalin when used in the same strengths 
(fig. 1). In the case of the adrenalin and of the suprarenalin, the 
solution was made from the commercial 1 in 1000 preparation : the 
hemisine tabloid was first made up to 1 in 1000 with Locke’s 
solution, and was then further diluted as required. This result 
may be expressed in another way — *00000031 gram per kilogram 
of body weight causes the minimal rise of blood pressure in rabbits. 
If the blood of the rabbit is taken as 5 per cent, of its body weight,* 
then *006 per million of blood is effective. When we compare 
this result with that of Ehrmann,! who found that *00002 gram 
per kilogram of body weight in a cat gave a rise of pressure 
which was just appreciable, we find a corroboration of Lesage’s | 
statement as to the comparative resistance of the cat to the 
effect of adrenalin. In an experiment on a cat of two and a half 
kilogrammes, a rise of blood pressure was given with *00003 g. in 
1 c.c. (*000012 g. per kilo) — that is, just over one-half the amount 
given by Ehrmann to produce his minimal result. It is interesting 
to compare this result with Schafer’s § suggestion, made before 
* Douglas, Journal of Physiology, vol. xxxiii. p. 493. 
t Loc. cit. 
t Arch, intern, de Pharmac. et de TMrap., li. p. 304, and C. R. Soc. Biol., 
1904, p. 665. 
§ Text-booTc of Physiology, vol. i. p. 957. 
PROC. ROY. SOC. EDIN. — YOL. XXVI. 
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