ADRENALS 



639 



value in ophthalmological practice. /Inhibition of the contraction 

 of the stomach, intestine, urinary bladder, and gall-bladder; con- 

 traction of the uterus, vas deferens, and seminal vesicles; dilatation 

 of the pupil and retraction of the nictitating membrane; stimulation 

 of the salivary and lachrymal secretions, are among its actions^ 

 (Langley). The curve of contraction of the skeletal muscles is 

 lengthened as in veratrine poisoning (p. 729), though to a less extent. 



Meltzer has shown that the dilatation of the pupil caused by 

 the intravenous injection of adrenalin is distinct, though fleeting, in 

 cats, less marked in rabbits. Subcutaneous injection has no effect. 

 Instillation of the drug into the conjunct! val sac is without effect 

 on the pupil in the normal rabbit's eye, but causes dilatation if the 

 superior cervical ganglion has been removed. 



jThe influence of adrenalin in increasing the sugar content of the 

 brood, and thus causing glycosuria J has been previously discussed 

 (P- 54 1 )- A new and interesting action has recently been added 

 by Cannon to the already long list of the effects of adrenalin, by the 

 discovery that small doses (o-ooi milligramme per kilo of body- 

 weight) and largeifdoses injected subcutaneously into cats shorten 

 the coagulation time of the bloodlto one-half or one-third of its 

 previous duration, /probably by Simulating the liver to greater 

 activity in discharging some substance or substances concerned in 

 clotting.! 



Methods for the detection and the assay of adrenalin in the small 

 quantities in which it can only be supposed to be present in physio- 

 logical liquids have been based upon certain of these actions. Such, 

 for example, is the extraordinary power of this active principle 

 that/a dose of one-millionth of a gramme per kilo of body-weight is 

 sufficient to cause a distinct effect upon the heart and bloodvessels J 

 (a rise of pressure of 14 millimetres Hg) when it is injected into 

 the veins of a mammal. The reaction is rendered more constant, 

 although less delicate, when the brain is previously destroyed and 

 the animal used as a spinal preparation. In pithed cats the assay 

 can be accurately performed to o-oi milligramme. Another delicate, 

 and for certain purposes a convenient, reaction for the detection 

 and the physiological assay of adrenalin is the perfusion test on the 

 legs of frogs already alluded to (p. 46). The dilatation of the pupil 

 in the excised eyeball of the frog, the contraction of stretched 

 artery rings (p. 66), the increase in the tone of isolated segments 

 of the uterus of rabbits or guinea-pigs, and the diminution in the 

 tone of isolated segments of intestine (Practical Exercises, p. 447), 

 have also been employed as physiological tests. 



A dilute solution of adrenalin chloride is used in medicine as 

 a styptic, and for reducing congestion in accessible parts. The 

 intense local anaemia which it causes when given subcutaneously 

 or by the mouth is one reason, perhaps the most important, for the 



