184 



Dr. A. D. Waller. On the 



[July 17, 



" On the 1 Blaze-currents ' of the Incubated Hen's Egg." By 

 Augustus D. Waller, M.D., F.R.S. Received July 17, — 

 Read December 4, 1902. 



(From the Physiological Laboratory of the University of London, S.W.) 



In previous communications to the Society, on the Eyeball,* on the 

 Skinj and on Leguminous Seeds, J I have reported the results of experi- 

 ments conducted by aid of an electrical criterion distinguishing between 

 the living and not-living state. 



The present communication contains the results of a series of syste- 

 matic observations on the hen's egg by aid of the same distinguishing 

 test — or blaze reaction, as I was led to designate it when it first came 

 under my observation in the case of the frog's eyeball. 



The case of the hen's egg is particularly interesting, for while we 

 cannot tell a priori with any assurance whether or no a dormant egg- 

 will give the reaction characteristic of living matter, we may — after 

 having learned by experience that it does not do so — expect to find 

 the reaction make its appearance with the progress of development by 

 incubation. And as a matter of fact, we find that this is what 

 happens. 



I first tested several eggs of unknown origin, bringing electrodes 

 into contact with the superior and inferior extremities of a vertical 

 short diameter of the egg laid upon its side. On account of the 

 resistance of the shell, a small piece was removed on each side, and 

 the electrodes brought into contact with the subjacent unbroken shell- 

 membrane. There was no blaze in either direction, but only slight 

 polarisation counter-currents of 0*0001 to 0*0002 volt. A similar 

 result was obtained when the yolk was laid bare and the superior 

 electrode applied directly to the cicatricula, both with the egg at 

 ordinary room-temperature (20°) and in an incubator at 37°. 



I then proceeded to test a series of ten fresh eggs reputed " fertile " 

 and fit for incubation. 



The results were briefly as follows : — 



Egg No. 1, at the end of 24 horns' incubation, gave a small ascend- 

 ing blaze. 



Egg No. 2, at the end of 48 hours, gave a similar but rather more 

 distinct effect. 



* " On the Blaze-currents of the Frog's Eyeball," ' Phil. Trans.,' B, vol. 194, 1901. 



+ " On Skin Currents. Part I. The Frog's Skin," ' Roy. Soc. Proe.,' June 6, 

 1901 ; " Part II. Observations on Cats," ibid., November 21, 1901 ; " Part III. 

 The Human Skin," ibid., May, 1902. 



t " An Attempt to Estimate the Vitality of Seeds by an Electrical Method," 

 ' Koy. Soc. Proc.,' vol. 68, p. 79. 



