Carbonic- oxide-hcemoglobin, &c, in the Magnetic Field. 505 



Although Faraday had shown that the blood is diamagnetic, and 

 Pliicker that the blood corpuscles are more decidedly diamagnetic than 

 the liquid in which they float, it was yet conceivable, though improba- 

 ble, that the iron-containing haemoglobin would prove to be a feebly 

 magnetic body, of which the true magnetic behaviour was concealed by 

 the substances with which it is associated in the blood corpuscles. 

 Whether haemoglobin proved to be magnetic or diamagnetic, it 

 obviously would be of great interest to examine the magnetic pro- 

 perties of the iron-containing substances which the blood-colouring 

 matter yields when it is decomposed by acids in the presence of 

 oxygen, and in the event of a difference between the magnetic beha- 

 viour of the mother-substance and its derivatives, to push the inquiry 

 in a direction likely to lead to the discovery of the cause of the 

 discrepancy. In pursuance of such an object I have been led to inquire 

 whether the pure blood-colouring matter in aqueous solution is an 

 electrolyte, and having discovered that it is one, to examine the results 

 of its electrolysis. On this part of my inquiry the statements which I 

 have to make in this paper are strictly preliminary, and, except in the 

 first most interesting particular that oxy-hsemoglobin and CO-hgemo- 

 globin separate in the first instance unchanged from their aqueous 

 solutions when these are subjected to very feeble currents, are to be 

 considered as liable to correction by future more extended work. 



3. The Electro-magnet employed in the present Research. 



The electro-magnet employed was constructed by Ladd many years 

 ago, and is sufficiently powerful to be employed for observations on 

 the rotation of the plane of polarisation of light. I had it fitted with 

 an accurately closing glass case and with adequate arrangements for 

 the proper suspension of the bodies under examination. I am not 

 possessed of instruments which would enable me to determine directly 

 the strength of the magnetic field employed in my several sets of 

 experiments. The Rev. ¥. J. Jervis-Smith, F.R.S., Millard Lecturer 

 in Experimental Mechanics in the University of Oxford, to whom I 

 had the pleasure of showing my experiments, had the great kindness 

 to make careful measurements of the coils, and has practically recon- 

 structed an electro-magnet similar in dimensions to mine, with the 

 same windings, and of which the iron core derived from a similar 

 instrument, made by Lacld, was probably identical in properties to 

 that in my electro-magnet. Using Professor Rowland's method for 

 determining the field, he obtained the following results : — 



Intensity of the earth's horizontal magnetic component at Oxford 

 = 0-18. 



Distance between faces of pole pieces, 3 cm. 



