THERMOGRAPHS OF REGIONAL DEATH 1 83 



Method of thermographs of regional death. — But I 



have found out another and distinct method for detect- 

 ing the effects of various agencies. And this method is 

 not only very interesting in itself, but it enables other 

 obscure problems to be attacked in a satisfactory manner. 

 It depends on the taking of Thermographs of Regional 

 Death. 



It is known that amongst the symptoms which occur at 

 some indefinite interval after death is that of discoloration. 

 Although this phenomenon is not concomitant with death, 

 yet the temperature-interval between the two can in many 

 cases be rendered definite. Thus for example, when the blue 

 Convolvulus is subjected to rising temperature at the normal 

 rate, it shows death-movement at 62*5° C. But there is as 

 yet no sign of discoloration. When the temperature, however, 

 rises to yo° C. the heating water begins to undergo discolora- 

 tion from the escaping cell sap. It would appear probable, 

 from various experiments which I have carried out, that 

 discoloration does not begin at the point of death-contrac- 

 tion, but occurs at or about the point of the subsequent 

 relaxation. But in the case of Convolvulus there is no strik- 

 ing change seen in the flower itself, for the loss of colouring 

 matter is gradual. In the style of Datura alba, however, we 

 have a more definite change of colour. This organ, from 

 being milk-white, becomes brown at a temperature of 64 C, 

 that is to say, 4 above the death-point, when the temperature 

 of the bath is rising at the ordinary rate. In the petals of 

 Sesbania coccineum, again, under similar conditions, the change 

 of colour is very striking. Rich crimson here turns into pale 

 blue, at a fairly definite temperature of 6y° C. The most marked 

 and easily observed of all these changes is seen, however, in 

 the mauve petals of Passiflora quadrangularis, which normally 

 becomes colourless at a temperature of 70 C. The filamentous 

 corona of the same flower again, in which the filaments are 

 barred by purple rings at intervals, loses its colour normally 

 at 68° C. The death-point of these filaments is, it should be 

 remembered, 6o° C. We thus find on raising the temperature 



