9 
The early anatomists observed that the juice of the medullary sub- 
stance of the capsulse atrabilianx (suprarenals) darkened upon expo- 
siue to the air, and called it atra hilis. It was not, however, until the 
nineteenth century that light was shed upon the cause of this color 
change. In 1856 Vulpian (75) observed that the medullary juice of 
the suprarenals tiuned emerald green and rose carmine when brought 
into contact with ferric chloride and iodine, respectively. These 
reactions were characteristic of this organ, and at once led to the sur- 
mise that the medulla of the gland contained a substance of physio- 
logical importance. 
Pellacani (62) as early as 1879 performed in Foa’s laboratory a 
series of very interesting experiments with extracts of the fresh 
organs, among which was a series of injections of adrenal extract into 
various animals. The capsules were excised, ground up in a mortar, 
and to this mass was added distilled water sufficient to filter, but not 
exceeding the amount needed for the injection. This liquid extract 
was filtered through linen and then paper, after which it was imme- 
diately injected. The greatest care was exercised both in the making 
of the extracts and in the preparation of the instruments, the latter 
being immersed in strong alcohol. Subcutaneous injections were 
made into dogs, cats, rabbits, guinea pigs, and frogs. A rise of tem- 
perature did not always occur, and in some of the animals there was a 
lowering of temperature, followed by death in from twelve to thirty 
hours for the more rapid cases of intoxication. The symptoms 
were general excitement, followed by paralysis, both sensory and motor, 
increasing weakness of the heart, lowering of temperature, 4-5°, fol- 
lowed by death. It is strange that PeUacani should have secured 
such characteristic adrenalin effects and yet observed that subcu- 
taneous injections were more toxic than intra-peritoneal ones, and 
that both of these methods of injection caused more pronounced and 
quicker effects than intravenous injections. Although he used ex- 
tracts of organs other than the adrenals, he found the latter to be 
more toxic and the following organs to be progressively less active: 
Muscle, liver, kidney, brain, milt. Five grams of clear extract of 
two suprarenals of rabbits injected into a 770-gram guinea pig 
caused death after twelve hours. Eighteen to twenty cubic centi- 
meters of extract of cat or guinea-pig adrenals proved very toxic for 
rabbits, whereas a higher dose, 1 gram, of lamb or heifer suprarenal 
extract was necessary to cause a like degree of toxicity. 
Mattei (53) repeated Pellacani’s experiments, but arrived at very 
different conclusions. In his conclusions he states that water ex- 
tracts of fresh organs injected into different animals does not cause 
any toxic action. The animals that die do so because of the after 
effects of the soluble organic matter of the decomposed tissues, which 
later cause septicemia. 
