104 THE SIMPLER NATURAL BASES 



supra-renal vein contains one part of adrenaline in I to 5 millions ; he 

 could not demonstrate adrenaline with certainty in the peripheral 

 blood. Stewart, who employed this method and that depending on the 

 contraction of the rabbit's uterus, also concludes that adrenaline is not 

 detectable in the general circulation, or indeed in blood from the supra- 

 renal vein, except during massage of the gland or stimulation of the 

 splanchnics, when there was respectively I : 500,000 and I : 1,000,000. 



Dale and Laidlaw [1912, 2] have used as a test object another 

 organ which is inhibited by adrenaline, viz. the non-pregnant uterus 

 of the cat. In a cat under chloroform and ether they find that the 

 blood from the supra-renal vein contains one part of adrenaline in from I 

 to 2 millions. After injection of pilocarpine this amount was increased 

 tenfold. 



The method which has been most widely used for the detection of 

 small quantities of adrenaline is based on mydriatic action, particu- 

 larly as applied to the excised eye of the frog. This test object was 

 first employed by S. J. and C. Meltzer [1904, i, 2] ; later Ehrmann 

 [1905] brought it into prominence by his experiments on body fluids 

 and by his claim that the excised eye, being much more sensitive than 

 the intact eye, can reveal adrenaline in a concentration of I : 10,000,000. 

 According to Borberg [1912] the sensitiveness is only one- tenth of 

 this. Schultz [1909, I] has elaborated the technique of this method 

 by measuring the pupil under the microscope. Hoskins [191 1] dis- 

 sected the eye, removed the lens and applied the fluid under examina- 

 tion directly to the iris ; in this way results were obtainable at a dilu- 

 tion of i : 5,000,000 and sometimes a positive result was noted at 

 I : 100,000,000, but a mydriatic effect is also shown by pituitary ex- 

 tract, iodothyrin, etc., which renders the method very uncertain when 

 applied to the detection of adrenaline in the blood. Schultz [1909, 2] 

 considers that Ehrmann overstated the sensitiveness of the method. 

 He writes : " At its very best the excised frog's eye as a pharmaco- 

 logical assay for adrenaline is inferior to the blood-pressure method. 

 As a qualitative test it is perhaps one of the most sensitive test-objects 

 known, but it is not a characteristic test (Comessatti, Meltzer) and 

 observations convince me that too much weight ought not to be at- 

 tached to results with it in clinical diagnosis ". This adverse opinion 

 is shared by Cameron [1906] and by Borberg [1912], but the 

 method at least has the advantage that it is applicable to very dilute 

 solutions and that it can be used by the chemist who cannot undertake 

 more elaborate animal experiments. According to Schultz the dilata- 

 tion time is a better index than the degree of mydriasis and one should 



