PUTEEFACTION AND INFECTION. 129 



on the rapidity of the passage of crystallized substances 

 into the vascular and non-vascular textures of the body,' 

 Dr. Bence Jones and Dr. Dupre communicated to the 

 Koyal Society in 1867 a highly interesting paper 'On 

 a Fluorescent Substance, resembling Quinine, in Ani- 

 mals.' '' They then showed that ' from every texture of 

 man and of some animals a fluorescent substance can 

 be extracted, which, when extracted, has a very close 

 optical and chemical resemblance to quinine.' They 

 therefore called it animal quinoidine. In dilute solu- 

 tions they found that the fluorescence of the animal 

 substance was not to be distinguished from that pro- 

 duced by quinine. When the solution was concentrated, 

 the colour of the light was of a decidedly greenish hue. 

 This latter observation is most in agreement with mine. 

 In all the infusions examined by me the fluorescent 

 light was a decided green, and not to be mistaken for 

 the blue light of quinine. 



The green colour is similar to that emitted by the 

 crystalline lens when a beam of violet light impinges 

 on it ; ' sending such a beam through any of the infu- 

 sions, the ' degradation ' of the violet to green is 

 strikingly illustrated. 



The foregoing statement refers to the deportment 

 of the infusions afber boiling and filtering. Prior to 

 boiling some of them were of a brilliant ruby colour ; 

 but even liere, when the layer of liquid between the 

 eye and the beam was not too thick, the green fluor- 

 escence could be seen through the red liquid. 



' Proceedings of the Eoyal Society, vol. xiv. 1865. 



2 Ibid. vol. XV. p. 73. 



• On plunging the eye into the beam of the electric lamp, trans- 

 mitted through violet glass, the moment the crystalline lens is seen 

 to fluoresce by a second observer, a blue shimmer is seen by the eye 

 on vrhich the beam falls. In the case of my own eye, I can always 

 readily tell when the fluoresence has set in. 



