EVOLUTION OF LIGHT. 889 



ally supposed. It is extremely difficult to burn a dead body. That 

 the presence of alcohol in the blood and tissues would increase the 

 inflammability of the dead or dying body, is possible. The commence- 

 ment of the combustion is clearly to be looked for in external, not in 

 internal causes. In all recorded instances, these cases have happened 

 either in the night, or at other times when fire, candles, or matches 

 were present, or might be supposed to be present; for frequently the 

 evidence of this may be destroyed by the spread of the combustion 

 itself. On the whole, it is rational to conclude, more especially as 

 habitual drunkards are incapable of exercising care in regard to these 

 sources of danger, that they have themselves, in a state of intoxication, 

 set fire, in falling, or otherwise, to their clothes or other combustible 

 materials, or that they have been reached by flames, otherwise occa- 

 sioned by the falling of candles, or by the emission of sparks from the 

 fire. It is significant that no case of spontaneous combustion has ever 

 happened in an animal. 



EVOLUTION OF LIGHT. 



A few examples are on record of the evolution of light from certain 

 excretions or discharges from the living human body ; but most of these 

 instances have been observed in diseased and dying persons. The per- 

 spiration after violent exercise, in one case, and the urinary excretion 

 in several instances, have been seen to display a decided luminosity ; 

 in the former case the luminous matter being even transferable to the 

 clothing. In three instances of persons in the last stage of phthisis, 

 a light, owing apparently to luminous breath, has been noticed playing 

 about the features ; the surface of a cancerous ulcer is also said to have 

 exhibited a similar appearance. In these cases, the light is supposed 

 to proceed from the slow oxidation of phosphorus or of some phos- 

 phuretted compound, resulting from the incipient decomposition of the 

 excretions, or from their containing some imperfectly oxidized com- 

 pound of phosphorus, which had accumulated in the blood, and become 

 eliminated in those fluids, but which would ordinarily be thrown off, in 

 the shape of alkaline or earthy phosphates. Phosphorus dissolved in 

 oil, injected into the veins of a dog (p. 828), produces a luminous con- 

 dition of the breath ; and a luminous state of the urine has been ob- 

 served in men who have taken phosphorus medicinally. It has been 

 suggested that, as a large number of the cases of luminous breath in 

 men have occurred in persons addicted to excessive drinking, certain 

 bodies, derived from the decomposition of alcohol, may impede the 

 proper oxidation of the phosphuretted compounds, which then escape 

 in the breath or other excretions. It is even presumed that the pres- 

 ence of such compounds in the blood may impart an unusual degree of 

 combustibility to the body. But the known compounds derivable from 

 alcohol, even aldehyde, are not so readily oxidizable as the imperfectly 

 oxidized compounds of phosphorus. This explanation is therefore 

 speculative; and the so-called cases of spontaneous combustion of the 

 bodies of intemperate persons, as just stated, are unfounded, and 

 capable of explanation on other and simpler grounds. 



