on the Nature and Properties of Alhnmen^ Sfc. 87 



is constant, and by no means so capricious as has been ima- 

 gined. 



15. Mr. Brande was, I believe, the first who applied electro- 

 chemical action to the detection of albumen (Phil. Trans. 

 1809 ; p. 373) ; and from the results of his experiments it ap- 

 pears, that when a solution of albumen (of white of egir) was 

 submitted to the action of a battery of 120 four-inch double 

 plates excited by dilute nitro-muriatic acid, rapid coagulation 

 took place at the negative, whilst only a thin film of albu- 

 men appeared at the positive electrode : the same results oc- 

 cured when a battery of 24- four-inch plates, " highly charged," 

 was substituted for the larger one, provided the wires forming 

 the electrodes were not more than half an inch distant from 

 each other; for when they were separated to eight inches, 

 or a smaller battery used, the albumen appeared only at the 

 positive electrode. When albumen of pus was substituted for 

 the white of egg, Mr. Brande found coagulation to take place 

 at both electrodes; but the size of the battery used in this 

 experiment is not mentioned. Albuminate of soda (procured 

 by boiling white of egg in water), when submitted to the action 

 of a battery of 60 four-inch plates, deposited albumen co- 

 piously at the negative electrode. From the results of his 

 experiments Mr. Brande appears to have been induced to be- 

 lieve that albumen, free or combined, always coagulated with 

 a strong electric current at the negative, and with a weak 

 current at the positive electrode. 



16. To obviate any error that might arise from the heat 

 evolved by the passage of electric currents of considerable 

 tension, I determined to employ small plates (2^ inches 

 square) excited only by weak brine ; these plates were ar- 

 ranged in separate jars, precisely on the principle of the cou- 

 ronne des tasscs. Thirty pairs of zinc and copper plates thus 

 arranged and excited, developed a current sufficiently ener- 

 getic to decompose water and saline solutions with rapidity, 

 and communicate a disagreeable shock extending beyond the 

 wrists ; but failed to heat perceptibly a piece of platina wire 

 (tito^ of an inch in diameter) sufficiently fine to be readily 

 ignited by a single voltaic pair presenting 4 square inches of 

 surface, excited by dilute sulphuric acid. 



17. I first examined the action of an electric current on 

 fluid albumen in as uncombined a state as it can readily be 

 obtained : for this purpose some dilute and prepared serum of 

 blood (1.) was placed in a glass cup, and by means of platinum 

 wires connected with the battery of 30 pairs, excited (as in all 

 the following experiments unless otherwise expressed) by 

 weak brine ; in a few minutes a considerable cloudy deposit 

 occurred in the proximity of the positive electrode, hut mthout 



