95o INFLUENCE OF DUCTLESS GLANDS ON METABOLISM. 
particular extirpation is toxic, especially for other animals which have 
been submitted to the operation. But it is probable that the blood 
of an animal dying slowly as the result of any disease, would be to 
some extent toxic, and the toxic principles would more powerfully affect 
animals whose resisting power had been lessened by a recent severe 
operation. However this may be, whether the suprarenal capsules do 
or do not destroy a toxic principle which is formed elsewhere, and which 
would otherwise accumulate in the blood, they unquestionably produce 
a material which has entirely different properties from those stated to 
be possessed by the blood of animals deprived of their capsules. This 
material, which is probably the basis of the internal secretion of the 
glands, has most active physiological properties. 
Hypodermic injection of extracts — General effects.— The action 
upon normal animals of extracts of suprarenal was first inves- 
tigated by Pellacani and Foil, 1 both alone and in conjunction. They 
injected subcutaneously extracts of the glands, made with water, and 
observed the symptoms which resulted. They found that animals 
(dogs) were killed by subcutaneous injection of extract of calf suprarenal. 
Their results were criticised by Alexander, 2 who pointed out that 
there was liability to chemical change in their preparations, and were 
not confirmed by other observers, but they are, nevertheless, in the 
main correct. 
In conjunction with G. Oliver, 3 I have myself made a number of 
observations upon the effect of subcutaneous injection of water and 
glycerin extracts of suprarenal. We found that the animals were 
usually unaffected by moderate doses, but with larger doses showed 
quickening and augmentation of the heart-beat, shallow and fast 
respirations, and fall of temperature. Guinea-pigs, we found, would 
stand a large subcutaneous dose of suprarenal extract without 
showing any symptoms at all, or with only a slight acceleration 
and increase of the force of the pulse. The same appeared to be 
the case with the cat and with the dog, unless a very large dose 
were injected, when the symptoms above enumerated became very 
' marked. Rabbits, on the other hand, were more susceptible to the 
influence of suprarenal extracts. If a large dose were given, the animal 
succumbed within half an hour. If, on the other hand, the dose was 
only moderate in quantity, it did not show any symptoms at all for 
some hours, but then it might suddenly succumb. This primary absence 
of symptoms was also noted by Foa and Pellacani in dogs. They state 
that in many of the animals which they experimented upon in this way, 
there were no symptoms at all apparent upon the day upon which the 
injection was given, but that the next morning the animal was usually 
found dead. The cause of death, it may be added, is not by any 
means clear. Foa and Pellacani have supposed that it may be due to 
paralysis of the respiratory centre, but the slight effect wdiich intra- 
venous injection of suprarenal extract produces upon this centre does 
not lend support to this conjecture. 
In frogs w r e found the effect of the water extract or decoction injected 
into the dorsal lymph sac was to produce a temporary paralysis, which 
1 Arch, per U sc. med., Torino, 1879, 1S80, tomes iii., iv., and vii. ; Arch. Hal. dc 
biol., Turin, 1883, p. 56. 
2 Beitr. 2. path. anat. u. z. allg. Path., Jena, 1892, Bd. xi. 
3 Journ. Physiol., Cambridge and London, 1895, vol. xviii. p. 235. 
