EVOLUTION OF ELECTRICITY. 633 



grains of phosphorus in solution, was injected into the crural vein of a dog, a 

 dense white vapor began to issue from the nostrils even before the syringe was 

 completely emptied, which became faintly luminous on the removal of the 

 lights: and, the injection being repeated with the same quantity, the expiration 

 immediately became beautifully luminous, resembling jets of pale-colored flame 

 pouring forth from the nostrils of the^animal. And the luminosity which has 

 been occasionally observed in the urine, 1 may fairly be imputed to an increase 

 in the quantity of unoxidized phosphorus which it seems normally to contain ; 

 its liberation taking place at a more rapid rate than its conversion into phos- 

 phoric acid ( 641), either through excessive excretion or through impeded re- 

 spiration. A case has been recorded by Kaster (loc. cit.) in which the body- 

 linen was rendered luminous by the perspiration after any violent exercise; 

 and here, too, the cause may be presumed to have been the same. On the 

 whole, then, we may conclude the occasional evolution of Light from the Hu- 

 man subject to be the consequence (when not an electrical phenomenon) of the 

 production of a phosphorescent compound at the expense of the disintegrating 

 tissues ; which compound passes off through one of the ordinary channels of 

 excretion. 



4. Evolution of Electricity. 



667. "When the vast variety of changes of condition to which the components 

 of the living body are subjected during the performance of its vital operations, 

 and the impossibility of the occurrence of any of these without some disturb- 

 ance of electric equilibrium, 9 are duly considered, the wonder is, not that such 

 disturbance should be occasionally so considerable as to make itself apparent, 

 but that it should be ordinarily so obscure as only to be detected by the most 

 careful search, and with the assistance of the most delicate instruments. The 

 researches of Prof. Matteucci, M. du Bois-Reymond, and others, however, have 

 now made it apparent, that there are no two parts of the body (save those which 

 correspond on the opposite sides) whose electrical condition is precisely the 

 same ; and that the diiferences between them are greater in proportion to the 

 diversity of the vital processes which are taking place in them, and to the 

 activity with which these are being carried on. Thus, Donne found that the 

 skin and most of the internal membranes are in opposite electrical states; and 

 Matteucci observed a considerable deflection of the needle of a delicate galvano- 

 meter, when the liver and stomach of a rabbit were connected with its platinum 

 electrodes. 3 ' More recently, Mr. Baxter has found that if one of the electrodes 

 be placed upon any part of the intestinal surface, and the other be inserted into 



1 "Casper's Wochenschrift," 1849, No. 15. A case has been recently put on record 

 (Biichner's Repert. B. viii. p. 342), in which the urine and semen of a patient who was 

 under treatment for impotence and spermatorrhoea, and who was employing phosphorus 

 as a remedy both internally and externally, were observed to be luminous. 



2 There is probably no instance of chemical union or decomposition, in which the electric 

 condition of the bodies concerned is not altered. Simple change of form, from solid to 

 liquid, or from liquid to gaseous, is attended with electric disturbance ; and this is greatly 

 increased when any separation takes place between substances that were previously united, 

 as when water containing a small quantity of saline matter is caused to evaporate and to 

 leave it behind. Heat, again, is continually generating Electricity ; for not only is a cur- 

 rent produced by the heating of two dissimilar metals in contact, but also by the unequal 

 heating of two parts of the same bar ; and though the effect is most striking in the case 

 of metals, it is by no means limited to them. And so constantly is Electricity generated 

 by the retardation of motion, as in friction, that it is not possible to rub together any two 

 substances, excepting such as are of the most perfect homogeneity (such as the fractured 

 surfaces of a broken bar) without the production of electric change, as well as of heat. 



3 See M. Becquerel's " Traite de I'Electricite," torn. i. p. 327, and torn. iv. p. 300. 



