166 THE DUCTLESS GLANDS 



rise of the blood-pressure on injection into the circulation 

 of a living animal. 



These observers employed glands mainly from the calf, 

 but also from the sheep, the guinea-pig, the cat, the dog, and 

 man. The physiological effects noticed were identical in all, 

 the only difference being in the case of diseased adrenals in 

 man (Addison's disease), in which case, if the disease were 

 extensive, no effect whatever was obtained. Extracts of the 

 glands were prepared with water, with alcohol of various 

 strengths, with glycerin, with ether, nigroin, and various other 

 solvents. They were made either by digesting an ascertained 

 weight of the fresh gland or of the dried gland in these men- 

 strua, or in addition by boiling the infusion for a few minutes. 

 The animals experimented upon were chiefly dogs, but some 

 experiments were also made upon cats, rabbits, and guinea- 

 pigs, and one upon a monkey. The extracts were usually 

 administered by intravenous injection, and the effects upon 

 the arterial system determined by the mercurial kymograph, 

 various kinds of plethysmographs, and perfusion through the 

 arterial system of the frog, after the nervous system had been 

 destroyed. 



The chief and fundamental effect noticed was contraction 

 of the arterioles. This contraction is so great as to produce 

 (even when concomitant vagus action has caused a great 

 diminution in the rate and force of the heart's beats) a large 

 rise of blood-pressure, and, in the case of the frog with its 

 nervous system destroyed, almost complete cessation of the 

 flow of circulating fluid through the arterioles. 



The usual effect of the injection is to produce constriction 

 of isolated organs. The limb shrinks (Fig. 39), the kidney 

 and spleen contract considerably, while the heart and larger 

 bloodvessels are enormously distended. But sometimes a 

 limb expands, and in some experiments one limb contracts 

 while another expands. In the later stages of experimentation 

 the passive dilatation is more usual. Hoskins, Gunning, and 

 Berry have recently reported that adrenin causes active 

 vasodilation of the muscles, while it gives rise to constriction 

 in the cutaneous vessels. Eemoving the skin from a limb 

 converts the usual contraction into an expansion. The rise 

 of blood -pressure is very largely due to constriction of the 

 splanchnic arterioles. But sometimes the intestine expands 



