230 



Dr. L. C. Wooldridge. 



[Mar. 31, 



wire has previously received permanent torsion in the opposite 

 direction. 



44. There is for all but very large magnetising forces a critical 

 point of torsion, for which temporary torsion does not affect the 

 temporary magnetic permeability. 



45. When the critical point of torsion is passed, the temporary 

 permeability increases with the torsion at first more rapidly than the 

 torsion, and afterwards more slowly until a maximum is reached and 

 the permeability begins to decline. 



46. When the wire has previously suffered excessive permanent 

 torsion, temporary torsion which has before produced increase of 

 permeability now produces decrease. 



47. The effect of temporary torsion on the temporary permeability 

 of unannealed piano-steel wire is in the same direction as with 

 annealed iron which has suffered excessive permanent torsion 

 (see 46). 



48. For a wide range of torsion the temporary permeability and 

 the permanent permeability of annealed iron are oppositely affected 

 by temporary torsion. 



49. Fluid pressure does not temporarily affect either the temporary 

 magnetic permeability of annealed iron, or the permanent magnetisa- 

 tion of hard steel, except, it may be, to a degree which is not com- 

 parable with that of the effect of stress applied in any one direction. 



50. The application, however, or the removal of fluid stress like 

 that of the stresses of compression, extension, and torsion, shakes out 

 from annealed iron a certain amount of residual magnetism. 



IV. "Note on a New Constituent of Blood Serum." By L. C. 

 Wooldridge, M.D., D.Sc., Besearch Scholar to the Grocers' 

 Company. Communicated by Dr. Pye- SMITH, F.R.S. 

 Received March 19, 1887. 



I wish in the present note to draw attention to a proteid substance 

 which exists in very small quantity in blood serum. Owing to the 

 difficulty of obtaining a sufficient amount, I shall not attempt to give 

 a complete description of its chemical characters, but shall confine 

 myself chiefly to its physiological properties which, I venture to 

 suggest, possess considerable interest. It is obtained by rendering 

 undiluted serum distinctly acid by means of dilute acetic or very 

 dilute (4 pro mille) sulphuric acid. Neutralisation does not cause its 

 precipitation ; the serum must have a strong acid reaction. It is 

 constantly present in the serum of dog's blood, and when collected by 

 the centrifuge it is precisely similar in physical characters to ordinary 



